1
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Barhoumi M, Liu J, Hübner W, Lefkidis G. Using single and double laser pulses on the molecular Ni 4@C 48H 36 system to design integrated nanospintronic units. Phys Chem Chem Phys 2024; 26:16070-16090. [PMID: 38780108 DOI: 10.1039/d4cp00523f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
The accomplishment of long-distance spin transfer scenarios between several magnetic centers is a big challenge for building and supporting spin-logic units for developing future all-optical magnetic unit operations. Using high-level quantum chemistry theory CCSD and EOM-CCSD, we systematically study the ultrafast laser-induced spin-dynamics process on a carbon-based material, to which four magnetic centers are attached. We show that the CCSD method with the 6-31G basis set calculation is sensitive to the C-Ni bond length. The spin density distribution, which is computed using EOM-CCSD with LanL2DZ+ECP calculations, Mulliken population analysis, including spin-orbit-coupling (SOC) and a magnetic field, fulfills the requirements for achieving spin dynamics processes. Different local spin-flip and spin-transfer processes are accomplished within the subpicosecond regime. The impact of the propagation direction of the laser pulse by switching their polar and the azimuthal angles in spherical coordinates on the spin dynamics processes is analyzed. Double laser pulses with time delay δt ≥ 200 × FWHM yield in a realistic magnetic field gradient selectively a lateral resolution, which corresponds to distances smaller than the CMOS scale (2 nm in 2024) while our system size is comparable to the CMOS scale. Here Λ and V processes with two quasi-degenerate intermediate levels are used. We propose a model of an integrated spin-logic processor created from an array of individual spin-logic blocks, which are realized by four magnetic centers Ni. The findings of this study demonstrate the enormous potential of using laser-induced spin dynamics as the fundamental mechanism for future molecular magnetic technology.
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Affiliation(s)
- Mohamed Barhoumi
- Deutsche Telekom Chair of Communication Networks, Institute of Communication Technology, Faculty of Electrical and Computer Engineering, Technische Universität Dresden, Dresden, Germany
- Quantum Communication Networks (QCNets) Research Group, Institute of Communication Technology, Faculty of Electrical and Computer Engineering, Technische Universität Dresden, Dresden, Germany
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern (RPTU) Kaiserslautern-Landau, P.O. Box 3049, 67653 Kaiserslautern, Germany.
| | - Jing Liu
- Institute of Theoretical Chemistry, Ulm University, 89081 Ulm, Germany
| | - Wolfgang Hübner
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern (RPTU) Kaiserslautern-Landau, P.O. Box 3049, 67653 Kaiserslautern, Germany.
| | - Georgios Lefkidis
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern (RPTU) Kaiserslautern-Landau, P.O. Box 3049, 67653 Kaiserslautern, Germany.
- Department of Engineering Mechanics, Northwestern Polytechnical University, 710072 Xi'an, China
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2
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Song S, Pinar Solé A, Matěj A, Li G, Stetsovych O, Soler D, Yang H, Telychko M, Li J, Kumar M, Chen Q, Edalatmanesh S, Brabec J, Veis L, Wu J, Jelinek P, Lu J. Highly entangled polyradical nanographene with coexisting strong correlation and topological frustration. Nat Chem 2024; 16:938-944. [PMID: 38374456 DOI: 10.1038/s41557-024-01453-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 01/17/2024] [Indexed: 02/21/2024]
Abstract
Open-shell nanographenes exhibit unconventional π-magnetism arising from topological frustration or strong electron-electron interaction. However, conventional design approaches are typically limited to a single magnetic origin, which can restrict the number of correlated spins or the type of magnetic ordering in open-shell nanographenes. Here we present a design strategy that combines topological frustration and electron-electron interactions to fabricate a large fully fused 'butterfly'-shaped tetraradical nanographene on Au(111). We employ bond-resolved scanning tunnelling microscopy and spin-excitation spectroscopy to resolve the molecular backbone and reveal the strongly correlated open-shell character, respectively. This nanographene contains four unpaired electrons with both ferromagnetic and anti-ferromagnetic interactions, harbouring a many-body singlet ground state and strong multi-spin entanglement, which is well described by many-body calculations. Furthermore, we study the magnetic properties and spin states in the nanographene using a nickelocene magnetic probe. The ability to imprint and characterize many-body strongly correlated spins in polyradical nanographenes paves the way for future advancements in quantum information technologies.
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Affiliation(s)
- Shaotang Song
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Andrés Pinar Solé
- Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute, Palacký University Olomouc, Olomouc, Czech Republic
| | - Adam Matěj
- Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute, Palacký University Olomouc, Olomouc, Czech Republic
| | - Guangwu Li
- Department of Chemistry, National University of Singapore, Singapore, Singapore
- Center of Single-Molecule Sciences, Frontiers Science Center for New Organic Matter, College of Electronic Information and Optical Engineering, Nankai University, Tianjin, China
| | | | - Diego Soler
- Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic
| | - Huimin Yang
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Mykola Telychko
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Jing Li
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Manish Kumar
- Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic
| | - Qifan Chen
- Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic
| | | | - Jiri Brabec
- Department of Theoretical Chemistry, J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Libor Veis
- Department of Theoretical Chemistry, J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic.
| | - Jishan Wu
- Department of Chemistry, National University of Singapore, Singapore, Singapore.
| | - Pavel Jelinek
- Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic.
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute, Palacký University Olomouc, Olomouc, Czech Republic.
| | - Jiong Lu
- Department of Chemistry, National University of Singapore, Singapore, Singapore.
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore.
- National University of Singapore (Suzhou) Research Institute, Suzhou, China.
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3
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Zuo L, Ye L, Li X, Xu RX, Yan Y, Zheng X. Unraveling the Nature of Spin Coupling in a Metal-Free Diradical: Theoretical Distinction of Ferromagnetic and Antiferromagnetic Interactions. J Phys Chem Lett 2024; 15:5761-5769. [PMID: 38776132 DOI: 10.1021/acs.jpclett.4c01063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
Metal-free diradicals based on polycyclic aromatic hydrocarbons are promising candidates for organic spintronics due to their stable magnetism and tunable spin coupling. However, distinguishing and elucidating the origins of ferromagnetic and antiferromagnetic interactions in these systems remain challenging. Here, we investigate the 2-OS diradical molecule sandwiched between gold electrodes using a combined density functional theory and hierarchical equations of motion approach. We find that the dihedral angle between the radical moieties controls the nature and strength of the intramolecular spin coupling, transitioning smoothly from antiferromagnetic to ferromagnetic as the angle increases. Distinct features in the inelastic electron tunneling spectra are identified that can discern the two coupling regimes, including spin excitation steps whose energies directly reveal the exchange coupling constant. Mechanical stretching of the junction is predicted to modulate the spectral line shapes by adjusting the hybridization of the molecular radicals with the electrodes. Our work elucidates the electronic origin of tunable spin interactions in 2-OS and provides spectroscopic fingerprints for characterizing magnetism in metal-free diradicals.
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Affiliation(s)
- Lijun Zuo
- Hefei National Research Center for Physical Sciences at the Microscale & Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Lyuzhou Ye
- Hefei National Research Center for Physical Sciences at the Microscale & Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Xiangyang Li
- Hefei National Research Center for Physical Sciences at the Microscale & Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Rui-Xue Xu
- Hefei National Research Center for Physical Sciences at the Microscale & Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - YiJing Yan
- Hefei National Research Center for Physical Sciences at the Microscale & Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Xiao Zheng
- Department of Chemistry, Fudan University, Shanghai 200433, P. R. China
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4
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Zhu X, Li K, Liu J, Wang Z, Ding Z, Su Y, Yang B, Yan K, Li G, Yu P. Topological Structure Realized in Cove-Edged Graphene Nanoribbons via Incorporation of Periodic Pentagon Rings. J Am Chem Soc 2024; 146:7152-7158. [PMID: 38421279 DOI: 10.1021/jacs.4c00270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Cove-edged zigzag graphene nanoribbons are predicted to show metallic, topological, or trivial semiconducting band structures, which are precisely determined by their cove offset positions at both edges as well as the ribbon width. However, due to the challenge of introducing coves into zigzag-edged graphene nanoribbons, only a few cove-edged graphene nanoribbons with trivial semiconducting bandgaps have been realized experimentally. Here, we report that the topological band structure can be realized in cove-edged graphene nanoribbons by embedding periodic pentagon rings on the cove edges through on-surface synthesis. Upon noncontact atomic force microscopy and scanning tunneling spectroscopy measurements, the chemical and electronic structures of cove-edged graphene nanoribbons with periodic pentagon rings have been characterized for different lengths. Combined with theoretical calculations, we find that upon inducing periodic pentagon rings the cove-edged graphene nanoribbons exhibit nontrivial topological structures. Our results provide insights for the design and understanding of the topological character in cove-edged graphene nanoribbons.
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Affiliation(s)
- Xujie Zhu
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Kezhen Li
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Jian Liu
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Zhou Wang
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Zhihao Ding
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Yunlong Su
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Bo Yang
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - KaKing Yan
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Gang Li
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
- ShanghaiTech Laboratory for Topological Physics, ShanghaiTech University, 201210 Shanghai, China
| | - Ping Yu
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
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5
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Jacobse PH, Sarker M, Saxena A, Zahl P, Wang Z, Berger E, Aluru NR, Sinitskii A, Crommie MF. Tunable Magnetic Coupling in Graphene Nanoribbon Quantum Dots. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2400473. [PMID: 38412424 DOI: 10.1002/smll.202400473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Indexed: 02/29/2024]
Abstract
Carbon-based quantum dots (QDs) enable flexible manipulation of electronic behavior at the nanoscale, but controlling their magnetic properties requires atomically precise structural control. While magnetism is observed in organic molecules and graphene nanoribbons (GNRs), GNR precursors enabling bottom-up fabrication of QDs with various spin ground states have not yet been reported. Here the development of a new GNR precursor that results in magnetic QD structures embedded in semiconducting GNRs is reported. Inserting one such molecule into the GNR backbone and graphitizing it results in a QD region hosting one unpaired electron. QDs composed of two precursor molecules exhibit nonmagnetic, antiferromagnetic, or antiferromagnetic ground states, depending on the structural details that determine the coupling behavior of the spins originating from each molecule. The synthesis of these QDs and the emergence of localized states are demonstrated through high-resolution atomic force microscopy (HR-AFM), scanning tunneling microscopy (STM) imaging, and spectroscopy, and the relationship between QD atomic structure and magnetic properties is uncovered. GNR QDs provide a useful platform for controlling the spin-degree of freedom in carbon-based nanostructures.
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Affiliation(s)
- Peter H Jacobse
- Department of Physics, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Mamun Sarker
- Department of Chemistry, University of Nebraska, Lincoln, NE, 68588, USA
- Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Anshul Saxena
- Walker Department of Mechanical Engineering, University of Texas, Austin, TX, 78712, USA
- Oden Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, TX, 78712, USA
| | - Percy Zahl
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Ziyi Wang
- Department of Physics, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Emma Berger
- Department of Physics, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Narayana R Aluru
- Walker Department of Mechanical Engineering, University of Texas, Austin, TX, 78712, USA
- Oden Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, TX, 78712, USA
| | - Alexander Sinitskii
- Department of Chemistry, University of Nebraska, Lincoln, NE, 68588, USA
- Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Michael F Crommie
- Department of Physics, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
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6
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Alcón I, Cummings AW, Roche S. Tailoring giant quantum transport anisotropy in nanoporous graphenes under electrostatic disorder. NANOSCALE HORIZONS 2024; 9:407-415. [PMID: 38275013 DOI: 10.1039/d3nh00416c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2024]
Abstract
During the last 15 years bottom-up on-surface synthesis has been demonstrated as an efficient way to synthesize carbon nanostructures with atomic precision, opening the door to unprecedented electronic control at the nanoscale. Nanoporous graphenes (NPGs) fabricated as two-dimensional arrays of graphene nanoribbons (GNRs) represent one of the key recent breakthroughs in the field. NPGs interestingly display in-plane transport anisotropy of charge carriers, and such anisotropy was shown to be tunable by modulating quantum interference. Herein, using large-scale quantum transport simulations, we show that electrical anisotropy in NPGs is not only resilient to disorder but can further be massively enhanced by its presence. This outcome paves the way to systematic engineering of quantum transport in NPGs as a novel concept for efficient quantum devices and architectures.
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Affiliation(s)
- Isaac Alcón
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
| | - Aron W Cummings
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
| | - Stephan Roche
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain.
- ICREA, Institució Catalana de Recerca i Estudis Avançats, 08070 Barcelona, Spain
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7
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Frezza F, Matěj A, Sánchez-Grande A, Carrera M, Mutombo P, Kumar M, Curiel D, Jelínek P. On-Surface Synthesis of a Radical 2D Supramolecular Organic Framework. J Am Chem Soc 2024; 146:3531-3538. [PMID: 38269436 PMCID: PMC10859929 DOI: 10.1021/jacs.3c13702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 01/26/2024]
Abstract
The design of supramolecular organic radical cages and frameworks is one of the main challenges in supramolecular chemistry. Their interesting material properties and wide applications make them very promising for (photo)redox catalysis, sensors, or host-guest spin-spin interactions. However, the high reactivity of radical organic systems makes the design of such supramolecular radical assemblies challenging. Here, we report the on-surface synthesis of a purely organic supramolecular radical framework on Au(111), by combining supramolecular and on-surface chemistry. We employ a tripodal precursor, functionalized with 7-azaindole groups that, catalyzed by a single gold atom on the surface, forms a radical molecular product constituted by a π-extended fluoradene-based radical core. The radical products self-assemble through hydrogen bonding, leading to extended 2D domains ordered in a Kagome-honeycomb lattice. This approach demonstrates the potential of on-surface synthesis for developing 2D supramolecular radical organic chemistry.
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Affiliation(s)
- Federico Frezza
- Institute
of Physics of Czech Academy of Sciences, Cukrovarnická 10, 16200 Prague 6 ,Czech Republic
- Faculty
of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Břehová 78/7,11519 Prague 1, Czech Republic
| | - Adam Matěj
- Institute
of Physics of Czech Academy of Sciences, Cukrovarnická 10, 16200 Prague 6 ,Czech Republic
- Department
of Physical Chemistry, Faculty of Science, Palacký University, 17. Listopadu 12, 779 00 Olomouc, Czech Republic
| | - Ana Sánchez-Grande
- Institute
of Physics of Czech Academy of Sciences, Cukrovarnická 10, 16200 Prague 6 ,Czech Republic
| | - Manuel Carrera
- Department
of Organic Chemistry, University of Murcia,
Campus of Espinardo, 30100 Murcia, Spain
| | - Pingo Mutombo
- Institute
of Physics of Czech Academy of Sciences, Cukrovarnická 10, 16200 Prague 6 ,Czech Republic
- Département
de Raffinage et Pétrochimie, Faculté de Pétrole,
Gaz et Énergies Renouvelables, Université
de Kinshasa, BP 127 Kinshasa XI, République
Démocratique du Congo
| | - Manish Kumar
- Institute
of Physics of Czech Academy of Sciences, Cukrovarnická 10, 16200 Prague 6 ,Czech Republic
| | - David Curiel
- Department
of Organic Chemistry, University of Murcia,
Campus of Espinardo, 30100 Murcia, Spain
| | - Pavel Jelínek
- Institute
of Physics of Czech Academy of Sciences, Cukrovarnická 10, 16200 Prague 6 ,Czech Republic
- CATRIN-RCPTM, Palacký University, Šlechtitelu° 27, 783 71 Olomouc, Czech Republic
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8
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Hieulle J, Garcia Fernandez C, Friedrich N, Vegliante A, Sanz S, Sánchez-Portal D, Haley MM, Casado J, Frederiksen T, Pascual JI. From Solution to Surface: Persistence of the Diradical Character of a Diindenoanthracene Derivative on a Metallic Substrate. J Phys Chem Lett 2023; 14:11506-11512. [PMID: 38088859 DOI: 10.1021/acs.jpclett.3c02401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Organic diradicals are envisioned as elementary building blocks for designing a new generation of spintronic devices and have been used in constructing prototypical field effect transistors and nonlinear optical devices. Open-shell systems, however, are also reactive, thus requiring design strategies to "protect" their radical character from the environment, especially when they are embedded in solid-state devices. Here, we report the persistence on a metallic surface of the diradical character of a diindeno[b,i]anthracene (DIAn) core protected by bulky end-groups. Our scanning tunneling spectroscopy measurements on single-molecules detected singlet-triplet excitations that were absent for DIAn species packed in assembled structures. Density functional theory simulations unravel that the molecular geometry on the metal substrate can crucially modify the value of the singlet-triplet gap via the delocalization of the radical sites. The persistence of the diradical character over metallic substrates is a promising finding for integrating radical-based materials into functional devices.
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Affiliation(s)
| | | | | | | | - Sofia Sanz
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
| | - Daniel Sánchez-Portal
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
- Centro de Física de Materiales MPC (CSIC/UPV-EHU), 20018 Donostia-San Sebastián, Spain
| | - Michael M Haley
- Department of Chemistry & Biochemistry and the Materials Science Institute, University of Oregon, Eugene, Oregon 97403-1253, United States
| | - Juan Casado
- Department of Physical Chemistry, University of Malaga, Campus de Teatinos s/n, 229071 Malaga, Spain
| | - Thomas Frederiksen
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
| | - José Ignacio Pascual
- CIC nanoGUNE-BRTA, 20018 Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
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9
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Zhang H, Lu J, Zhao XJ, Li B, Zhou H, Zhang Y, Niu G, Fu B, Gao L, Tan YZ, Cai J. Length-Dependent Magnetic Evolution of Anthenes on Au(111). Angew Chem Int Ed Engl 2023; 62:e202315216. [PMID: 37933811 DOI: 10.1002/anie.202315216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 11/08/2023]
Abstract
Nanographenes with zigzag edges, for example, anthenes, exhibit a unique nonbonding π-electron state, which can be described as a spin-polarized edge state that yields specific magnetic ground state. However, prior researches on the magnetism of anthenes with varying lengths on a surface is lacking. This study systematically fabricated anthenes with inherent zigzag carbon atoms of different lengths ranging from bisanthene to hexanthene. Their magnetic evolution on the Au(111) surface was analyzed through bond-resolved scanning probe techniques and density functional theory calculations. The analyses revealed a transition in magnetic properties associated with the length of the anthenes, arising from the imbalance between hybridization energy and the Coulomb repulsion between valence electrons. With the increasing length of the anthenes, the ground state transforms gradually from a closed-shell to an antiferromagnetic open-shell singlet, exhibiting a weak exchange coupling of 4 meV and a charge transfer-induced doublet. Therefore, this study formulated a chemically tunable platform to explore size-dependent π magnetism at the atomic scale, providing a framework for research in organic spintronics.
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Affiliation(s)
- Hui Zhang
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
| | - Jianchen Lu
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
| | - Xin-Jing Zhao
- State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Baijin Li
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
| | - Hangjing Zhou
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
| | - Yong Zhang
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
| | - Gefei Niu
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
| | - Boyu Fu
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
| | - Lei Gao
- Faculty of Science, Kunming University of Science and Technology, Kunming, 650500, China
| | - Yuan-Zhi Tan
- State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Jinming Cai
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
- Southwest United Graduate School, Kunming, 650093, China
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10
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Erpenbeck A, Gull E, Cohen G. Shaping Electronic Flows with Strongly Correlated Physics. NANO LETTERS 2023; 23:10480-10489. [PMID: 37955307 DOI: 10.1021/acs.nanolett.3c03067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
Nonequilibrium quantum transport is of central importance in nanotechnology. Its description requires the understanding of strong electronic correlations that couple atomic-scale phenomena to the nanoscale. So far, research in correlated transport has focused predominantly on few-channel transport, precluding the investigation of cross-scale effects. Recent theoretical advances enable the solution of models that capture the interplay between quantum correlations and confinement beyond a few channels. This problem is the focus of this study. We consider an atomic impurity embedded in a metallic nanosheet spanning two leads, showing that transport is significantly altered by tuning only the phase of a single local hopping parameter. Furthermore─depending on this phase─correlations reshape the electronic flow throughout the sheet, either funneling it through the impurity or scattering it away from a much larger region. This demonstrates the potential for quantum correlations to bridge length scales in the design of nanoelectronic devices and sensors.
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Affiliation(s)
- Andre Erpenbeck
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Emanuel Gull
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Guy Cohen
- The Raymond and Beverley Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 6997801, Israel
- School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
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11
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Chen B, Xue L, Han Y, Yang Z, Zhang YJ. Magnetic semiconducting borophenes and their derivatives. Phys Chem Chem Phys 2023; 25:30897-30902. [PMID: 37955266 DOI: 10.1039/d3cp04069k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
Two semiconducting borophenes with layer-dependent magnetism are predicted based on spin-polarized density functional theory. Both monolayer borophenes are ferromagnetic. One is composed of B3 and B15 triangular motifs, exhibiting bipolar spin polarization and a magnetic moment of 1.00 μB per primitive cell. The other consists of B15 triangular motifs, possessing a Curie temperature of about 437 K and a magnetic moment of 3.00 μB per primitive cell. B atoms located between the triangular motifs are essential for inducing ferromagnetism in monolayer borophenes. However, bilayer borophenes with high-symmetry stacking orders are nonmagnetic. Furthermore, magnetic boron nanotubes and fullerenes could be made of monolayer borophenes. Finally, we propose to fabricate these magnetic semiconducting borophenes from the buckled triangular structure of borophenes via selective electron beam ionization of B atoms by scanning transmission electron microscopy.
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Affiliation(s)
- Bo Chen
- College of Physics, Taiyuan University of Technology, Taiyuan 030024, P. R. China.
| | - Lin Xue
- College of Physics, Taiyuan University of Technology, Taiyuan 030024, P. R. China.
| | - Yan Han
- College of Physics, Taiyuan University of Technology, Taiyuan 030024, P. R. China.
| | - Zhi Yang
- College of Physics, Taiyuan University of Technology, Taiyuan 030024, P. R. China.
| | - Yong-Jia Zhang
- College of Physics, Taiyuan University of Technology, Taiyuan 030024, P. R. China.
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12
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Calupitan JP, Berdonces-Layunta A, Aguilar-Galindo F, Vilas-Varela M, Peña D, Casanova D, Corso M, de Oteyza DG, Wang T. Emergence of π-Magnetism in Fused Aza-Triangulenes: Symmetry and Charge Transfer Effects. NANO LETTERS 2023; 23:9832-9840. [PMID: 37870305 PMCID: PMC10722538 DOI: 10.1021/acs.nanolett.3c02586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 10/16/2023] [Accepted: 10/17/2023] [Indexed: 10/24/2023]
Abstract
On-surface synthesis has paved the way toward the fabrication and characterization of conjugated carbon-based molecular materials that exhibit π-magnetism such as triangulenes. Aza-triangulene, a nitrogen-substituted derivative, was recently shown to display rich on-surface chemistry, offering an ideal platform to investigate structure-property relations regarding spin-selective charge transfer and magnetic fingerprints. Herein, we study electronic changes upon fusion of single molecules into larger dimeric derivatives. We show that the closed-shell structure of aza-triangulene on Ag(111) leads to closed-shell dimers covalently coupled through sterically accessible carbon atoms. Meanwhile, its open-shell structure on Au(111) leads to coupling via atoms displaying a high spin density, resulting in symmetric or asymmetric products. Interestingly, whereas all dimers on Au(111) exhibit similar charge transfer properties, only asymmetric ones show magnetic fingerprints due to spin-selective charge transfer. These results expose clear relationships among molecular symmetry, charge transfer, and spin states of π-conjugated carbon-based nanostructures.
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Affiliation(s)
- Jan Patrick Calupitan
- Centro
de Física de Materiales (CFM-MPC), CSIC-UPV/EHU, 20018 San Sebastián, Spain
- Donostia
International Physics Center, 20018 San Sebastián, Spain
| | - Alejandro Berdonces-Layunta
- Centro
de Física de Materiales (CFM-MPC), CSIC-UPV/EHU, 20018 San Sebastián, Spain
- Donostia
International Physics Center, 20018 San Sebastián, Spain
| | - Fernando Aguilar-Galindo
- Departamento
de Química, Universidad Autónoma
de Madrid, 28049 Madrid, Spain
- Institute
for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Manuel Vilas-Varela
- Centro
Singular de Investigación en Química Biolóxica
e Materiais Moleculares (CiQUS) and Departamento de Química
Orgánica, Universidade de Santiago
de Compostela, 15782 Santiago de Compostela, Spain
| | - Diego Peña
- Centro
Singular de Investigación en Química Biolóxica
e Materiais Moleculares (CiQUS) and Departamento de Química
Orgánica, Universidade de Santiago
de Compostela, 15782 Santiago de Compostela, Spain
| | - David Casanova
- Donostia
International Physics Center, 20018 San Sebastián, Spain
- Ikerbasque, Basque Foundation
for Science, 48009 Bilbao, Spain
| | - Martina Corso
- Centro
de Física de Materiales (CFM-MPC), CSIC-UPV/EHU, 20018 San Sebastián, Spain
- Donostia
International Physics Center, 20018 San Sebastián, Spain
| | - Dimas G. de Oteyza
- Centro
de Física de Materiales (CFM-MPC), CSIC-UPV/EHU, 20018 San Sebastián, Spain
- Donostia
International Physics Center, 20018 San Sebastián, Spain
- Nanomaterials
and Nanotechnology Research Center (CINN), CSIC-UNIOVI-PA, 33940 El Entrego, Spain
| | - Tao Wang
- Centro
de Física de Materiales (CFM-MPC), CSIC-UPV/EHU, 20018 San Sebastián, Spain
- Donostia
International Physics Center, 20018 San Sebastián, Spain
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13
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Krane N, Turco E, Bernhardt A, Jacob D, Gandus G, Passerone D, Luisier M, Juríček M, Fasel R, Fernández-Rossier J, Ruffieux P. Exchange Interactions and Intermolecular Hybridization in a Spin- 1/ 2 Nanographene Dimer. NANO LETTERS 2023; 23:9353-9359. [PMID: 37819646 DOI: 10.1021/acs.nanolett.3c02633] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Phenalenyl is a radical nanographene with a triangular shape hosting an unpaired electron with spin S = 1/2. The open-shell nature of the phenalenyl is expected to be retained in covalently bonded networks. As a first step, we report synthesis of the phenalenyl dimer by combining in-solution synthesis and on-surface activation and its characterization on Au(111) and on a NaCl decoupling layer by means of inelastic electron tunneling spectroscopy (IETS). IETS shows inelastic steps that are identified as singlet-triplet excitation arising from interphenalenyl exchange. Spin excitation energies with and without the NaCl decoupling layer are 48 and 41 meV, respectively, indicating significant renormalization due to exchange with Au(111) electrons. Furthermore, third-neighbor hopping-induced interphenalenyl hybridization is fundamental to explaining the position-dependent bias asymmetry of the inelastic steps and activation of kinetic interphenalenyl exchange. Our results pave the way for bottom-up synthesis of S = 1/2 spin-lattices with large exchange interactions.
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Affiliation(s)
- N Krane
- nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600 Dübendorf, Switzerland
| | - E Turco
- nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600 Dübendorf, Switzerland
| | - A Bernhardt
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - D Jacob
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Universidad del País Vasco UPV/EHU, Av. Tolosa 72, E-20018 San Sebastián, Spain
- Basque Foundation for Science, IKERBASQUE, Plaza Euskadi 5, E-48009 Bilbao, Spain
| | - G Gandus
- Integrated Systems Laboratory, ETH Zürich, Gloriastrasse 35, 8092 Zürich, Switzerland
| | - D Passerone
- nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600 Dübendorf, Switzerland
| | - M Luisier
- Integrated Systems Laboratory, ETH Zürich, Gloriastrasse 35, 8092 Zürich, Switzerland
| | - M Juríček
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - R Fasel
- nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600 Dübendorf, Switzerland
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - J Fernández-Rossier
- International Iberian Nanotechnology Laboratory (INL), Avenida Mestre José Veiga s/n, 4715-330 Braga, Portugal
| | - P Ruffieux
- nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600 Dübendorf, Switzerland
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14
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Lawrence J, He Y, Wei H, Su J, Song S, Wania Rodrigues A, Miravet D, Hawrylak P, Zhao J, Wu J, Lu J. Topological Design and Synthesis of High-Spin Aza-triangulenes without Jahn-Teller Distortions. ACS NANO 2023; 17:20237-20245. [PMID: 37791737 DOI: 10.1021/acsnano.3c05974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
The atomic doping of open-shell nanographenes enables precise tuning of their electronic and magnetic states, which is crucial for their promising potential applications in optoelectronics and spintronics. Among this intriguing class of molecules, triangulenes stand out with their size-dependent electronic properties and spin states, which can also be influenced by the presence of dopant atoms and functional groups. However, the occurrence of Jahn-Teller distortions in such systems can have a crucial impact on their total spin and requires further theoretical and experimental investigation. In this study, we examine the nitrogen-doped aza-triangulene series via a combination of density functional theory and on-surface synthesis. We identify a general trend in the calculated spin states of aza-[n]triangulenes of various sizes, separating them into two symmetry classes, one of which features molecules that are predicted to undergo Jahn-Teller distortions that reduce their symmetry and thus their total spin. We link this behavior to the location of the central nitrogen atom relative to the two underlying carbon sublattices of the molecules. Consequently, our findings reveal that neutral centrally doped aza-triangulenes have one less radical than their undoped counterparts, irrespective of their predicted symmetry. We follow this by demonstrating the on-surface synthesis of π-extended aza-[5]triangulene, a large member of the higher symmetry class without Jahn-Teller distortions, via a simple one-step annealing process on Cu(111) and Au(111). Using scanning probe microscopy and spectroscopy combined with theoretical calculations, we prove that the molecule is positively charged on the Au(111) substrate, with a high-spin quintet state of S = 2, the same total spin as undoped neutral [5]triangulene. Our study uncovers the correlation between the dopant position and the radical nature of high-spin nanographenes, providing a strategy for the design and development of these nanographenes for various applications.
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Affiliation(s)
- James Lawrence
- Department of Chemistry, National University of Singapore, 117543 Singapore
| | - Yuanyuan He
- College of Material and Textile Engineering, Key Laboratory of Yarn Materials Forming and Composite Processing Technology of Zhejiang Province, Jiaxing University, Jiaxing 314001, Zhejiang, People's Republic of China
| | - Haipeng Wei
- Department of Chemistry, National University of Singapore, 117543 Singapore
| | - Jie Su
- Department of Chemistry, National University of Singapore, 117543 Singapore
| | - Shaotang Song
- Department of Chemistry, National University of Singapore, 117543 Singapore
| | | | - Daniel Miravet
- Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Pawel Hawrylak
- Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- Institute for Functional Intelligent Materials, National University of Singapore, 117544 Singapore
| | - Jianwei Zhao
- College of Material and Textile Engineering, Key Laboratory of Yarn Materials Forming and Composite Processing Technology of Zhejiang Province, Jiaxing University, Jiaxing 314001, Zhejiang, People's Republic of China
| | - Jishan Wu
- Department of Chemistry, National University of Singapore, 117543 Singapore
| | - Jiong Lu
- Department of Chemistry, National University of Singapore, 117543 Singapore
- Institute for Functional Intelligent Materials, National University of Singapore, 117544 Singapore
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15
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Brede J, Merino-Díez N, Berdonces-Layunta A, Sanz S, Domínguez-Celorrio A, Lobo-Checa J, Vilas-Varela M, Peña D, Frederiksen T, Pascual JI, de Oteyza DG, Serrate D. Detecting the spin-polarization of edge states in graphene nanoribbons. Nat Commun 2023; 14:6677. [PMID: 37865684 PMCID: PMC10590394 DOI: 10.1038/s41467-023-42436-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 10/11/2023] [Indexed: 10/23/2023] Open
Abstract
Low dimensional carbon-based materials can show intrinsic magnetism associated to p-electrons in open-shell π-conjugated systems. Chemical design provides atomically precise control of the π-electron cloud, which makes them promising for nanoscale magnetic devices. However, direct verification of their spatially resolved spin-moment remains elusive. Here, we report the spin-polarization of chiral graphene nanoribbons (one-dimensional strips of graphene with alternating zig-zag and arm-chair boundaries), obtained by means of spin-polarized scanning tunnelling microscopy. We extract the energy-dependent spin-moment distribution of spatially extended edge states with π-orbital character, thus beyond localized magnetic moments at radical or defective carbon sites. Guided by mean-field Hubbard calculations, we demonstrate that electron correlations are responsible for the spin-splitting of the electronic structure. Our versatile platform utilizes a ferromagnetic substrate that stabilizes the organic magnetic moments against thermal and quantum fluctuations, while being fully compatible with on-surface synthesis of the rapidly growing class of nanographenes.
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Grants
- E13-20R Gobierno de Aragón
- E12-20R Gobierno de Aragón
- ED431G2019/03 Xunta de Galicia
- 863098 EC | EU Framework Programme for Research and Innovation H2020 | H2020 Priority Excellent Science | H2020 Future and Emerging Technologies (H2020 Excellent Science - Future and Emerging Technologies)
- PRE-2021-2-0190 Eusko Jaurlaritza (Basque Government)
- PIBA-2020-1-0014 Eusko Jaurlaritza (Basque Government)
- 863098 EC | EU Framework Programme for Research and Innovation H2020 | H2020 Priority Excellent Science | H2020 Future and Emerging Technologies (H2020 Excellent Science - Future and Emerging Technologies)
- Ministerio de Ciencia, Innovación y Universidades | Agencia Estatal de Investigación, Grant no PID2019-107338RB-C64 Eureopean Comission | European Regional Developement Funds | Interreg, Grant no EFA194/16 TNSI
- Ministerio de Ciencia, Innovación y Universidades | Agencia Estatal de Investigación, Grant no PID2019-107338RB-C64
- Ministerio de Ciencia, Innovación y Universidades | Agencia Estatal de Investigación, Grant no PID2019-107338RB-C62
- Ministerio de Ciencia, Innovación y Universidades | Agencia Estatal de Investigación, Grant no PID2020–115406GB-I00
- Ministerio de Ciencia, Innovación y Universidades | Agencia Estatal de Investigación, Grant no PID2019-107338RB-C61 Maria de Maeztu Excellence Program, Grant no CEX2020-001038-M Diputación Foral de Guipuzkoa | Guipuzkoa Next, grant no 2021-CIEN-000069-01
- Ministerio de Ciencia, Innovación y Universidades | Agencia Estatal de Investigación, Grant no PID2019-107338RB-C63
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Affiliation(s)
- Jens Brede
- Donostia International Physics Center, San Sebastián, E-20018, Spain
- Centro de Física de Materiales (MPC), CSIC-UPV/EHU, San Sebastián, E-20018, Spain
| | - Nestor Merino-Díez
- Donostia International Physics Center, San Sebastián, E-20018, Spain
- Centro de Física de Materiales (MPC), CSIC-UPV/EHU, San Sebastián, E-20018, Spain
| | - Alejandro Berdonces-Layunta
- Donostia International Physics Center, San Sebastián, E-20018, Spain
- Centro de Física de Materiales (MPC), CSIC-UPV/EHU, San Sebastián, E-20018, Spain
| | - Sofía Sanz
- Donostia International Physics Center, San Sebastián, E-20018, Spain
| | - Amelia Domínguez-Celorrio
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza, E-50009, Spain
| | - Jorge Lobo-Checa
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza, E-50009, Spain
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, Zaragoza, E-50009, Spain
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, Zaragoza, E-50009, Spain
| | - Manuel Vilas-Varela
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela, E-15782, Spain
| | - Diego Peña
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela, E-15782, Spain
| | - Thomas Frederiksen
- Donostia International Physics Center, San Sebastián, E-20018, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, E-48013, Spain
| | - José I Pascual
- Ikerbasque, Basque Foundation for Science, Bilbao, E-48013, Spain.
- CIC nanoGUNE BRTA, San Sebastián, E-20018, Spain.
| | - Dimas G de Oteyza
- Donostia International Physics Center, San Sebastián, E-20018, Spain.
- Centro de Física de Materiales (MPC), CSIC-UPV/EHU, San Sebastián, E-20018, Spain.
- Nanomaterials and Nanotechnology Research Center (CINN), CSIC-UNIOVI-PA, El Entrego, E-33940, Spain.
| | - David Serrate
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza, E-50009, Spain.
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, Zaragoza, E-50009, Spain.
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, Zaragoza, E-50009, Spain.
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16
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Vilas-Varela M, Romero-Lara F, Vegliante A, Calupitan JP, Martínez A, Meyer L, Uriarte-Amiano U, Friedrich N, Wang D, Schulz F, Koval NE, Sandoval-Salinas ME, Casanova D, Corso M, Artacho E, Peña D, Pascual JI. On-Surface Synthesis and Characterization of a High-Spin Aza-[5]-Triangulene. Angew Chem Int Ed Engl 2023; 62:e202307884. [PMID: 37604782 DOI: 10.1002/anie.202307884] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/11/2023] [Accepted: 08/17/2023] [Indexed: 08/23/2023]
Abstract
Triangulenes are a class of open-shell triangular graphene flakes with total spin increasing with their size. In the last years, on-surface-synthesis strategies have permitted fabricating and engineering triangulenes of various sizes and structures with atomic precision. However, direct proof of the increasing total spin with their size remains elusive. In this work, we report the combined in-solution and on-surface synthesis of a large nitrogen-doped triangulene (aza-[5]-triangulene) on a Au(111) surface, and the detection of its high-spin ground state. Bond-resolved scanning tunneling microscopy images uncovered radical states distributed along the zigzag edges, which were detected as weak zero-bias resonances in scanning tunneling spectra. These spectral features reveal the partial Kondo screening of a high-spin state. Through a combination of several simulation tools, we find that the observed distribution of radical states is explained by a quintet ground state (S=2), instead of the quartet state (S=3/2) expected for the neutral species. This confirms that electron transfer to the metal substrate raises the spin of the ground state. We further provide a qualitative description of the change of (anti)aromaticity introduced by N-substitution, and its role in the charge stabilization on a surface, resulting in an S=2 aza-triangulene on Au(111).
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Affiliation(s)
- Manuel Vilas-Varela
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782-, Santiago de Compostela, Spain
| | | | | | - Jan Patrick Calupitan
- Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center, 20018, Donostia-San Sebastián, Spain
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastián, Spain
| | - Adrián Martínez
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782-, Santiago de Compostela, Spain
| | - Lorenz Meyer
- CIC nanoGUNE-BRTA, 20018, Donostia-San Sebastián, Spain
| | | | | | - Dongfei Wang
- CIC nanoGUNE-BRTA, 20018, Donostia-San Sebastián, Spain
| | - Fabian Schulz
- CIC nanoGUNE-BRTA, 20018, Donostia-San Sebastián, Spain
| | | | | | - David Casanova
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48009, Bilbao, Spain
| | - Martina Corso
- Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center, 20018, Donostia-San Sebastián, Spain
| | - Emilio Artacho
- CIC nanoGUNE-BRTA, 20018, Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48009, Bilbao, Spain
- Theory of Condensed Matter, Cavendish Laboratory, University of Cambridge, J. J. Thomson Ave., Cambridge, CB3 0HE, UK
| | - Diego Peña
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782-, Santiago de Compostela, Spain
| | - José Ignacio Pascual
- CIC nanoGUNE-BRTA, 20018, Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48009, Bilbao, Spain
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17
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Barhoumi M, Liu J, Lefkidis G, Hübner W. Laser-induced ultrafast spin-transfer processes in non-linear zigzag carbon chain systems. Phys Chem Chem Phys 2023; 25:24563-24580. [PMID: 37661835 DOI: 10.1039/d3cp02483k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
We combine the high-level quantum chemistry theory CCSD and EOM-CCSD together with local and global Λ processes to investigate the details of the laser-induced ultrafast spin manipulation scenarios in non-linear zigzag carbon chain systems Ni2@C32H32 and Ni2@C36H36. The spin density distribution, which is calculated on each many-body state using a Mulliken population analysis, fulfills the requirements to accomplish the spin dynamics processes. Various spin-flip and spin-transfer scenarios are accomplished. All the spin-dynamics processes can be achieved within subpicosecond times. Under the influence of a magnetic field, we find that the spin-transfer scenarios are preserved, while the local spin-flip scenario on a Ni atom can be significantly inhibited depending on the strength of the magnetic field. The impact of the propagation direction of the laser pulse on the spin dynamics processes by varying their polar and azimuthal angles in spherical coordinates is investigated. Additionally, we find that double laser pulses successfully induce the spin-transfer processes. Our outcomes underline the significant potential of carbon chain systems as building blocks for developing future all-optical integrated logic processing units.
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Affiliation(s)
- Mohamed Barhoumi
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern (RPTU) Kaiserslautern-Landau, P.O. Box 3049, 67653 Kaiserslautern, Germany.
| | - Jing Liu
- Institute of Theoretical Chemistry, Ulm University, 89081 Ulm, Germany
| | - Georgios Lefkidis
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern (RPTU) Kaiserslautern-Landau, P.O. Box 3049, 67653 Kaiserslautern, Germany.
| | - Wolfgang Hübner
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern (RPTU) Kaiserslautern-Landau, P.O. Box 3049, 67653 Kaiserslautern, Germany.
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18
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Barhoumi M, Liu J, Lefkidis G, Hübner W. Ultrafast control of laser-induced spin-dynamics scenarios on two-dimensional Ni3@C63H54 magnetic system. J Chem Phys 2023; 159:084304. [PMID: 37638625 DOI: 10.1063/5.0158160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/07/2023] [Indexed: 08/29/2023] Open
Abstract
The concept of building logically functional networks employing spintronics or magnetic heterostructures is becoming more and more popular today. Incorporating logical segments into a circuit needs physical bonds between the magnetic molecules or clusters involved. In this framework, we systematically study ultrafast laser-induced spin-manipulation scenarios on a closed system of three carbon chains to which three Ni atoms are attached. After the inclusion of spin-orbit coupling and an external magnetic field, different ultrafast spin dynamics scenarios involving spin-flip and long-distance spin-transfer processes are achieved by various appropriately well-tailored time-resolved laser pulses within subpicosecond timescales. We additionally study the various effects of an external magnetic field on spin-flip and spin-transfer processes. Moreover, we obtain spin-dynamics processes induced by a double laser pulse, rather than a single one. We suggest enhancing the spatial addressability of spin-flip and spin-transfer processes. The findings presented in this article will improve our knowledge of the magnetic properties of carbon-based magnetic molecular structures. They also support the relevant experimental realization of spin dynamics and their potential applications in future molecular spintronics devices.
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Affiliation(s)
- Mohamed Barhoumi
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern (RPTU) Kaiserslautern-Landau, P.O. Box 3049, 67653 Kaiserslautern, Germany
| | - Jing Liu
- Institute of Theoretical Chemistry, Ulm University, 89081 Ulm, Germany
| | - Georgios Lefkidis
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern (RPTU) Kaiserslautern-Landau, P.O. Box 3049, 67653 Kaiserslautern, Germany
| | - Wolfgang Hübner
- Department of Physics, Rheinland-Pfälzische Technische Universität Kaiserslautern (RPTU) Kaiserslautern-Landau, P.O. Box 3049, 67653 Kaiserslautern, Germany
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19
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Du Q, Su X, Liu Y, Jiang Y, Li C, Yan K, Ortiz R, Frederiksen T, Wang S, Yu P. Orbital-symmetry effects on magnetic exchange in open-shell nanographenes. Nat Commun 2023; 14:4802. [PMID: 37558678 PMCID: PMC10412602 DOI: 10.1038/s41467-023-40542-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 08/01/2023] [Indexed: 08/11/2023] Open
Abstract
Open-shell nanographenes appear as promising candidates for future applications in spintronics and quantum technologies. A critical aspect to realize this potential is to design and control the magnetic exchange. Here, we reveal the effects of frontier orbital symmetries on the magnetic coupling in diradical nanographenes through scanning probe microscope measurements and different levels of theoretical calculations. In these open-shell nanographenes, the exchange energy exhibits a remarkable variation between 20 and 160 meV. Theoretical calculations reveal that frontier orbital symmetries play a key role in affecting the magnetic coupling on such a large scale. Moreover, a triradical nanographene is demonstrated for investigating the magnetic interaction among three unpaired electrons with unequal magnetic exchange, in agreement with Heisenberg spin model calculations. Our results provide insights into both theoretical design and experimental realization of nanographene materials with different exchange interactions through tuning the orbital symmetry, potentially useful for realizing magnetically operable graphene-based nanomaterials.
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Affiliation(s)
- Qingyang Du
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Xuelei Su
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Yufeng Liu
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yashi Jiang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Can Li
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - KaKing Yan
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Ricardo Ortiz
- Donostia International Physics Center (DIPC) - UPV/EHU, 20018, San Sebastián, Spain.
| | - Thomas Frederiksen
- Donostia International Physics Center (DIPC) - UPV/EHU, 20018, San Sebastián, Spain.
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain.
| | - Shiyong Wang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China.
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Ping Yu
- School of Physical Science and Technology, ShanghaiTech University, 201210, Shanghai, China.
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20
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Turco E, Bernhardt A, Krane N, Valenta L, Fasel R, Juríček M, Ruffieux P. Observation of the Magnetic Ground State of the Two Smallest Triangular Nanographenes. JACS AU 2023; 3:1358-1364. [PMID: 37234116 PMCID: PMC10207087 DOI: 10.1021/jacsau.2c00666] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/02/2023] [Accepted: 02/02/2023] [Indexed: 05/27/2023]
Abstract
Fusion of three benzene rings in a triangular fashion gives rise to the smallest open-shell graphene fragment, the phenalenyl radical, whose π-extension leads to an entire family of non-Kekulé triangular nanographenes with high-spin ground states. Here, we report the first synthesis of unsubstituted phenalenyl on a Au(111) surface, which is achieved by combining in-solution synthesis of the hydro-precursor and on-surface activation by atomic manipulation, using the tip of a scanning tunneling microscope. Single-molecule structural and electronic characterizations confirm its open-shell S = 1/2 ground state that gives rise to Kondo screening on the Au(111) surface. In addition, we compare the phenalenyl's electronic properties with those of triangulene, the second homologue in the series, whose S = 1 ground state induces an underscreened Kondo effect. Our results set a new lower size limit in the on-surface synthesis of magnetic nanographenes that can serve as building blocks for the realization of new exotic quantum phases of matter.
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Affiliation(s)
- Elia Turco
- nanotech@surfaces
Laboratory, Empa−Swiss Federal Laboratories
for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Annika Bernhardt
- Department
of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Nils Krane
- nanotech@surfaces
Laboratory, Empa−Swiss Federal Laboratories
for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Leoš Valenta
- Department
of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Roman Fasel
- nanotech@surfaces
Laboratory, Empa−Swiss Federal Laboratories
for Materials Science and Technology, 8600 Dübendorf, Switzerland
- Department
of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Michal Juríček
- Department
of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Pascal Ruffieux
- nanotech@surfaces
Laboratory, Empa−Swiss Federal Laboratories
for Materials Science and Technology, 8600 Dübendorf, Switzerland
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21
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Ma C, Wang J, Ma H, Yin R, Zhao XJ, Du H, Meng X, Ke Y, Hu W, Li B, Tan S, Tan YZ, Yang J, Wang B. Remote-Triggered Domino-like Cyclodehydrogenation in Second-Layer Topological Graphene Nanoribbons. J Am Chem Soc 2023; 145:10126-10135. [PMID: 37097709 DOI: 10.1021/jacs.3c00563] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
Cyclodehydrogenation reactions in the on-surface synthesis of graphene nanoribbons (GNRs) usually involve a series of Csp2-Csp2 and/or Csp2-Csp3 couplings and just happen on uncovered metal or metal oxide surfaces. It is still a big challenge to extend the growth of second-layer GNRs in the absence of necessary catalytic sites. Here, we demonstrate the direct growth of topologically nontrivial GNRs via multistep Csp2-Csp2 and Csp2-Csp3 couplings in the second layer by annealing designed bowtie-shaped precursor molecules over one monolayer on the Au(111) surface. After annealing at 700 K, most of the polymerized chains that appear in the second layer covalently link to the first-layer GNRs that have partially undergone graphitization. Following annealing at 780 K, the second-layer GNRs are formed and linked to the first-layer GNRs. Benefiting from the minimized local steric hindrance of the precursors, we suggest that the second-layer GNRs undergo domino-like cyclodehydrogenation reactions that are remotely triggered at the link. We confirm the quasi-freestanding behaviors in the second-layer GNRs by measuring the quasiparticle energy gap of topological bands and the tunable Kondo resonance from topological end spins using scanning tunneling microscopy/spectroscopy combined with first-principles calculations. Our findings pave the avenue to diverse multilayer graphene nanostructures with designer quantum spins and topological states for quantum information science.
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Affiliation(s)
- Chuanxu Ma
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
| | - Jufeng Wang
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Huanhuan Ma
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ruoting Yin
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xin-Jing Zhao
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory for Physical Chemistry of Solid Surfaces, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Hongjian Du
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
| | - Xinyong Meng
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yifan Ke
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Wei Hu
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
| | - Bin Li
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
| | - Shijing Tan
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
| | - Yuan-Zhi Tan
- Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory for Physical Chemistry of Solid Surfaces, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005, China
| | - Jinlong Yang
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
| | - Bing Wang
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
- New Cornerstone Science Laboratory, Shenzhen 518054, China
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22
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Yan Y, Zheng F, Qie B, Lu J, Jiang H, Zhu Z, Sun Q. Triangle Counting Rule: An Approach to Forecast the Magnetic Properties of Benzenoid Polycyclic Hydrocarbons. J Phys Chem Lett 2023; 14:3193-3198. [PMID: 36971433 DOI: 10.1021/acs.jpclett.3c00570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Open-shell benzenoid polycyclic hydrocarbons (BPHs) are promising materials for future quantum applications. However, the search for and realization of open-shell BPHs with desired properties is a challenging task due to the gigantic chemical space of BPHs, requiring new strategies for both theoretical understanding and experimental advancement. In this work, by building a structure database of BPHs through graphical enumeration, performing data-driven analysis, and combining tight-binding and mean-field Hubbard calculations, we discovered that the number of the internal vertices of the BPH graphs is closely correlated to their open-shell characters. We further established a simple rule, the triangle counting rule, to predict the magnetic ground states of BPHs. These findings not only provide a database of open-shell BPHs, but also extend the well-known Lieb's theorem and Ovchinnikov's rule and provide a straightforward method for designing open-shell carbon nanostructures. These insights may aid in the exploration of emerging quantum phases and the development of magnetic carbon materials for technology applications.
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Affiliation(s)
- Yuyi Yan
- Materials Genome Institute, Shanghai University, Shanghai 200444, China
| | - Fengru Zheng
- Materials Genome Institute, Shanghai University, Shanghai 200444, China
| | - Boyu Qie
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Kavli Energy NanoScience Institute, Berkeley, California 94720, United States
| | - Jiayi Lu
- Materials Genome Institute, Shanghai University, Shanghai 200444, China
| | - Hao Jiang
- Materials Genome Institute, Shanghai University, Shanghai 200444, China
| | - Zhiwen Zhu
- Materials Genome Institute, Shanghai University, Shanghai 200444, China
| | - Qiang Sun
- Materials Genome Institute, Shanghai University, Shanghai 200444, China
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23
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Cahlík A, Liu D, Zengin B, Taskin M, Schwenk J, Natterer FD. A versatile platform for graphene nanoribbon synthesis, electronic decoupling, and spin polarized measurements. NANOSCALE ADVANCES 2023; 5:1722-1728. [PMID: 36926566 PMCID: PMC10012868 DOI: 10.1039/d2na00668e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
The on-surface synthesis of nano-graphenes has led the charge in prototyping structures with perspectives beyond silicon-based technology. Following reports of open-shell systems in graphene-nanoribbons (GNRs), a flurry of research activity was directed at investigating their magnetic properties with a keen eye for spintronic applications. Although the synthesis of nano-graphenes is usually carried out on Au(111), the substrate is difficult to use for electronic decoupling and spin-polarized measurements. Using a binary alloy Cu3Au(111), we show possibilities for gold-like on-surface synthesis compatible with spin polarization and electronic decoupling known from copper. We prepare copper oxide layers, demonstrate the synthesis of GNRs, and grow thermally stable magnetic Co islands. We functionalize the tip of a scanning tunneling microscope with carbon-monoxide, nickelocene, or attach Co clusters for high-resolution imaging, magnetic sensing, or spin-polarized measurements. This versatile platform will be a valuable tool in the advanced study of magnetic nano-graphenes.
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Affiliation(s)
- Aleš Cahlík
- Department of Physics, University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Danyang Liu
- Department of Physics, University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Berk Zengin
- Department of Physics, University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Mert Taskin
- Department of Physics, University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Johannes Schwenk
- Institute of Physics, EPFL Station 3 CH-1015 Lausanne Switzerland
| | - Fabian Donat Natterer
- Department of Physics, University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
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24
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Wang T, Fan Q, Zhu J. Steering On-Surface Reactions by Kinetic and Thermodynamic Strategies. J Phys Chem Lett 2023; 14:2251-2262. [PMID: 36821589 DOI: 10.1021/acs.jpclett.3c00001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
On-surface synthesis has emerged as a powerful tool to fabricate various functional low-dimensional nanostructures with atomic precision, thus becoming a promising platform for the preparation of next-generation semiconductive, magnetic, and topological nanodevices. With the aid of scanning tunneling microscopy/spectroscopy and noncontact atomic force microscopy, both the chemical structures and physical properties of the obtained products can be well characterized. A major challenge in this field is how to efficiently steer reaction pathways and improve the yield/quality of products. To address this problem, in recent years various kinetic and thermodynamic strategies have been successfully employed to control on-surface reactions. In this Perspective, we discuss these strategies in view of basic reaction steps on surfaces, including molecular adsorption, diffusion, and reaction. We hope this Perspective will help readers to deepen the understanding of the mechanisms of on-surface reactions and rationally design reaction procedures for the fabrication of high-quality functional nanomaterials on surfaces.
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Affiliation(s)
- Tao Wang
- Department of Pharmacy, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, and National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
- Donostia International Physics Center, San Sebastián 20018, Spain
| | - Qitang Fan
- Hefei National Research Center for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, P. R. China
| | - Junfa Zhu
- Department of Pharmacy, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, and National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, P. R. China
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25
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Lipton-Duffin J, MacLeod J. Innovations in nanosynthesis: emerging techniques for precision, scalability, and spatial control in reactions of organic molecules on solid surfaces. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:183001. [PMID: 36876935 DOI: 10.1088/1361-648x/acbc01] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
The surface science-based approach to synthesising new organic materials on surfaces has gained considerable attention in recent years, owing to its success in facilitating the formation of novel 0D, 1D and 2D architectures. The primary mechanism used to date has been the catalytic transformation of small organic molecules through substrate-enabled reactions. In this Topical Review, we provide an overview of alternate approaches to controlling molecular reactions on surfaces. These approaches include light, electron and ion-initiated reactions, electrospray ionisation deposition-based techniques, collisions of neutral atoms and molecules, and superhydrogenation. We focus on the opportunities afforded by these alternative approaches, in particular where they may offer advantages in terms of selectivity, spatial control or scalability.
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Affiliation(s)
- Josh Lipton-Duffin
- School of Chemistry and Physics and Centre for Materials Science, Queensland University of Technology (QUT), Brisbane, Australia
- Central Analytical Research Facility, Queensland University of Technology (QUT), Brisbane, Australia
| | - Jennifer MacLeod
- School of Chemistry and Physics and Centre for Materials Science, Queensland University of Technology (QUT), Brisbane, Australia
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26
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Zuzak R, Castro-Esteban J, Engelund M, Pérez D, Peña D, Godlewski S. On-Surface Synthesis of Nanographenes and Graphene Nanoribbons on Titanium Dioxide. ACS NANO 2023; 17:2580-2587. [PMID: 36692226 PMCID: PMC9933590 DOI: 10.1021/acsnano.2c10416] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 01/19/2023] [Indexed: 06/17/2023]
Abstract
The formation of two types of nanographenes from custom designed and synthesized molecular precursors has been achieved through thermally induced intramolecular cyclodehydrogenation reactions on the semiconducting TiO2(110)-(1×1) surface, confirmed by the combination of high-resolution scanning tunneling microscopy (STM) and spectroscopy (STS) measurements, and corroborated by theoretical modeling. The application of this protocol on differently shaped molecular precursors demonstrates the ability to induce a highly efficient planarization reaction both within strained pentahelicenes as well as between vicinal phenyl rings. Additionally, by the combination of successive Ullmann-type polymerization and cyclodehydrogenation reactions, the archetypic 7-armchair graphene nanoribbons (7-AGNRs) have also been fabricated on the titanium dioxide surface from the standard 10,10'-dibromo-9,9'-bianthryl (DBBA) molecular precursors. These examples of the effective cyclodehydrogenative planarization processes provide perspectives for the rational design and synthesis of molecular nanostructures on semiconductors.
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Affiliation(s)
- Rafal Zuzak
- Centre
for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty
of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, PL 30-348 Krakow, Poland
| | - Jesus Castro-Esteban
- Centro
de Investigación en Química Biolóxica e Materiais
Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782 Santiago
de Compostela, Spain
| | - Mads Engelund
- Espeem
S.A.R.L. (espeem.com), 12 Cité Franz Leesbierg, L-4206 Esch-sur-Alzette, Luxembourg
| | - Dolores Pérez
- Centro
de Investigación en Química Biolóxica e Materiais
Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782 Santiago
de Compostela, Spain
| | - Diego Peña
- Centro
de Investigación en Química Biolóxica e Materiais
Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782 Santiago
de Compostela, Spain
| | - Szymon Godlewski
- Centre
for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty
of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, PL 30-348 Krakow, Poland
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27
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Steering Large Magnetic Exchange Coupling in Nanographenes near the Closed-Shell to Open-Shell Transition. J Am Chem Soc 2023; 145:2968-2974. [PMID: 36708335 DOI: 10.1021/jacs.2c11431] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The design of open-shell carbon-based nanomaterials is at the vanguard of materials science, steered by their beneficial magnetic properties like weaker spin-orbit coupling than that of transition metal atoms and larger spin delocalization, which are of potential relevance for future spintronics and quantum technologies. A key parameter in magnetic materials is the magnetic exchange coupling (MEC) between unpaired spins, which should be large enough to allow device operation at practical temperatures. In this work, we theoretically and experimentally explore three distinct families of nanographenes (NGs) (A, B, and C) featuring majority zigzag peripheries. Through many-body calculations, we identify a transition from a closed-shell ground state to an open-shell ground state upon an increase of the molecular size. Our predictions indicate that the largest MEC for open-shell NGs occurs in proximity to the transition between closed-shell and open-shell states. Such predictions are corroborated by the on-surface syntheses and structural, electronic, and magnetic characterizations of three NGs (A[3,5], B[4,5], and C[4,3]), which are the smallest open-shell systems in their respective chemical families and are thus located the closest to the transition boundary. Notably, two of the NGs (B[4,5] and C[4,3]) feature record values of MEC (close to 200 meV) measured on the Au(111) surface. Our strategy for maximizing the MEC provides perspectives for designing carbon nanomaterials with robust magnetic ground states.
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28
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Quantum nanomagnets in on-surface metal-free porphyrin chains. Nat Chem 2023; 15:53-60. [PMID: 36280765 DOI: 10.1038/s41557-022-01061-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/09/2022] [Indexed: 01/14/2023]
Abstract
Unlike classic spins, quantum magnets are spin systems that interact via the exchange interaction and exhibit collective quantum behaviours, such as fractional excitations. Molecular magnetism often stems from d/f-transition metals, but their spin-orbit coupling and crystal field induce a significant magnetic anisotropy, breaking the rotation symmetry of quantum spins. Thus, it is of great importance to build quantum nanomagnets in metal-free systems. Here we have synthesized individual quantum nanomagnets based on metal-free multi-porphyrin systems. Covalent chains of two to five porphyrins were first prepared on Au(111) under ultrahigh vacuum, and hydrogen atoms were then removed from selected carbons using the tip of a scanning tunnelling microscope. The conversion of specific porphyrin units to their radical or biradical state enabled the tuning of intra- and inter-porphyrin magnetic coupling. Characterization of the collective magnetic properties of the resulting chains showed that the constructed S = 1/2 antiferromagnets display a gapped excitation, whereas the S = 1 antiferromagnets exhibit distinct end states between even- and odd-numbered spin chains, consistent with Heisenberg model calculations.
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29
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Friedrich N, Menchón RE, Pozo I, Hieulle J, Vegliante A, Li J, Sánchez-Portal D, Peña D, Garcia-Lekue A, Pascual JI. Addressing Electron Spins Embedded in Metallic Graphene Nanoribbons. ACS NANO 2022; 16:14819-14826. [PMID: 36037149 PMCID: PMC9527809 DOI: 10.1021/acsnano.2c05673] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 08/17/2022] [Indexed: 06/15/2023]
Abstract
Spin-hosting graphene nanostructures are promising metal-free systems for elementary quantum spintronic devices. Conventionally, spins are protected from quenching by electronic band gaps, which also hinder electronic access to their quantum state. Here, we present a narrow graphene nanoribbon substitutionally doped with boron heteroatoms that combines a metallic character with the presence of localized spin 1/2 states in its interior. The ribbon was fabricated by on-surface synthesis on a Au(111) substrate. Transport measurements through ribbons suspended between the tip and the sample of a scanning tunneling microscope revealed their ballistic behavior, characteristic of metallic nanowires. Conductance spectra show fingerprints of localized spin states in the form of Kondo resonances and inelastic tunneling excitations. Density functional theory rationalizes the metallic character of the graphene nanoribbon due to the partial depopulation of the valence band induced by the boron atoms. The transferred charge builds localized magnetic moments around the boron atoms. The orthogonal symmetry of the spin-hosting state's and the valence band's wave functions protects them from mixing, maintaining the spin states localized. The combination of ballistic transport and spin localization into a single graphene nanoribbon offers the perspective of electronically addressing and controlling carbon spins in real device architectures.
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Affiliation(s)
| | - Rodrigo E. Menchón
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
| | - Iago Pozo
- CiQUS,
Centro Singular de Investigación en Química Biolóxica
e Materiais Moleculares, 15705 Santiago de Compostela, Spain
| | | | | | - Jingcheng Li
- CIC
nanoGUNE-BRTA, 20018 Donostia-San Sebastián, Spain
| | - Daniel Sánchez-Portal
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
- Centro
de Física de Materiales CSIC-UPV/EHU, 20018 Donostia-San Sebastián, Spain
| | - Diego Peña
- CiQUS,
Centro Singular de Investigación en Química Biolóxica
e Materiais Moleculares, 15705 Santiago de Compostela, Spain
| | - Aran Garcia-Lekue
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
- Ikerbasque,
Basque Foundation for Science, 48013 Bilbao, Spain
| | - José Ignacio Pascual
- CIC
nanoGUNE-BRTA, 20018 Donostia-San Sebastián, Spain
- Ikerbasque,
Basque Foundation for Science, 48013 Bilbao, Spain
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30
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de Oteyza DG, Frederiksen T. Carbon-based nanostructures as a versatile platform for tunable π-magnetism. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:443001. [PMID: 35977474 DOI: 10.1088/1361-648x/ac8a7f] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 08/17/2022] [Indexed: 06/15/2023]
Abstract
Emergence ofπ-magnetism in open-shell nanographenes has been theoretically predicted decades ago but their experimental characterization was elusive due to the strong chemical reactivity that makes their synthesis and stabilization difficult. In recent years, on-surface synthesis under vacuum conditions has provided unprecedented opportunities for atomically precise engineering of nanographenes, which in combination with scanning probe techniques have led to a substantial progress in our capabilities to realize localized electron spin states and to control electron spin interactions at the atomic scale. Here we review the essential concepts and the remarkable advances in the last few years, and outline the versatility of carbon-basedπ-magnetic materials as an interesting platform for applications in spintronics and quantum technologies.
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Affiliation(s)
- Dimas G de Oteyza
- Nanomaterials and Nanotechnology Research Center (CINN), CSIC-UNIOVI-PA, E-33940 El Entrego, Spain
- Donostia International Physics Center (DIPC)-UPV/EHU, E-20018 San Sebastián, Spain
| | - Thomas Frederiksen
- Donostia International Physics Center (DIPC)-UPV/EHU, E-20018 San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, E-48013 Bilbao, Spain
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31
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Wang D, Wang Z, Wu S, Yin X, Tang CS, Feng YP, Wu J, Wee ATS. Realizing Two-Dimensional Supramolecular Arrays of a Spin Molecule via Halogen Bonding. ACS NANOSCIENCE AU 2022; 2:333-340. [PMID: 37102064 PMCID: PMC10125333 DOI: 10.1021/acsnanoscienceau.2c00005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Well-ordered spin arrays are desirable for next-generation molecule-based magnetic devices, yet their synthetic method remains a challenging task. Herein, we demonstrate the realization of two-dimensional supramolecular spin arrays on surfaces via halogen-bonding molecular self-assembly. A bromine-terminated perchlorotriphenylmethyl radical with net carbon spin was synthesized and deposited on Au(111) to achieve two-dimensional supramolecular spin arrays. By taking advantage of the diversity of halogen bonds, five supramolecular spin arrays form and are probed by low-temperature scanning tunneling microscopy at the single-molecule level. First-principles calculations verify that the formation of three distinct types of halogen bonds can be used to tailor supramolecular spin arrays via molecular coverage and annealing temperature. Our work suggests that supramolecular self-assembly can be a promising method to engineer two-dimensional molecular spin arrays.
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Affiliation(s)
- Dingguan Wang
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore
| | - Zishen Wang
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore
| | - Shaofei Wu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Xinmao Yin
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, Singapore 117603, Singapore
- Shanghai Key Laboratory of High Temperature Superconductors, Physics Department, Shanghai University, Shanghai 200444, China
| | - Chi Sin Tang
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, Singapore 117603, Singapore
- Institute of Materials Research and Engineering, ASTAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Yuan Ping Feng
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore
| | - Jishan Wu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Andrew T S Wee
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore
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32
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Sun K, Silveira OJ, Saito S, Sagisaka K, Yamaguchi S, Foster AS, Kawai S. Manipulation of Spin Polarization in Boron-Substituted Graphene Nanoribbons. ACS NANO 2022; 16:11244-11250. [PMID: 35730993 DOI: 10.1021/acsnano.2c04563] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The design of magnetic topological states due to spin polarization in an extended π carbon system has great potential in spintronics application. Although magnetic zigzag edges in graphene nanoribbons (GNRs) have been investigated earlier, real-space observation and manipulation of spin polarization in a heteroatom substituted system remains challenging. Here, we investigate a zero-bias peak at a boron site embedded at the center of an armchair-type GNR on a AuSiX/Au(111) surface with a combination of low-temperature scanning tunneling microscopy/spectroscopy and density functional theory calculations. After the tip-induced removal of a Si atom connected to two adjacent boron atoms, a clear Kondo resonance peak appeared and was further split by an applied magnetic field of 12 T. This magnetic state can be relayed along the longitudinal axis of the GNR by sequential removal of Si atoms.
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Affiliation(s)
- Kewei Sun
- Research Center for Advanced Measurement and Characterization, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| | - Orlando J Silveira
- Department of Applied Physics, Aalto University, PO Box 11100, FI-00076 Aalto, Finland
| | - Shohei Saito
- Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Keisuke Sagisaka
- Research Center for Advanced Measurement and Characterization, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
| | - Shigehiro Yamaguchi
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo, Chikusa, Nagoya 464-8602, Japan
| | - Adam S Foster
- Department of Applied Physics, Aalto University, PO Box 11100, FI-00076 Aalto, Finland
- WPI Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Shigeki Kawai
- Research Center for Advanced Measurement and Characterization, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
- Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571, Japan
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33
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Zhu X, Liu Y, Pu W, Liu FZ, Xue Z, Sun Z, Yan K, Yu P. On-Surface Synthesis of C144 Hexagonal Coronoid with Zigzag Edges. ACS NANO 2022; 16:10600-10607. [PMID: 35730577 DOI: 10.1021/acsnano.2c02163] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Coronoids as polycyclic aromatic macrocycles enclosing a cavity have attracted a lot of attention due to their distinctive molecular and electronic structures. They can be also regarded as nanoporous graphene molecules whose electronic properties are critically dependent on the size and topology of their outer and inner peripheries. However, because of their synthetic challenges, the extended hexagonal coronoids with zigzag outer edges have not been reported yet. Here, we report the on-surface synthesis of C144 hexagonal coronoid with outer zigzag edges on a designed precursor undergoing hierarchical Ullmann coupling and cyclodehydrogenation on the Au(111) surface. The molecular structure is unambiguously characterized by bond-resolved noncontact atomic force microscopy imaging. The electronic properties are further investigated by scanning tunneling spectroscopy measurements, in combination with the density functional theory calculations. Moreover, the values of the harmonic oscillator model of aromaticity are derived from calculations that suggest that the molecular structure is ideally represented by Clar's model. Our results provide approaches toward realizing a hexagonal coronoid with zigzag edges, potentially inspiring fabrication of hexagonal zigzag coronoids with multiple radical characters in the future.
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Affiliation(s)
- Xujie Zhu
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Yanan Liu
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Weiwen Pu
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Fang-Zi Liu
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Zhijie Xue
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Zhaoru Sun
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - KaKing Yan
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Ping Yu
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
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34
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Biswas K, Urbani M, Sánchez-Grande A, Soler-Polo D, Lauwaet K, Matěj A, Mutombo P, Veis L, Brabec J, Pernal K, Gallego JM, Miranda R, Écija D, Jelínek P, Torres T, Urgel JI. Interplay between π-Conjugation and Exchange Magnetism in One-Dimensional Porphyrinoid Polymers. J Am Chem Soc 2022; 144:12725-12731. [PMID: 35817408 PMCID: PMC9305978 DOI: 10.1021/jacs.2c02700] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The synthesis of novel polymeric materials with porphyrinoid compounds as key components of the repeating units attracts widespread interest from several scientific fields in view of their extraordinary variety of functional properties with potential applications in a wide range of highly significant technologies. The vast majority of such polymers present a closed-shell ground state, and, only recently, as the result of improved synthetic strategies, the engineering of open-shell porphyrinoid polymers with spin delocalization along the conjugation length has been achieved. Here, we present a combined strategy toward the fabrication of one-dimensional porphyrinoid-based polymers homocoupled via surface-catalyzed [3 + 3] cycloaromatization of isopropyl substituents on Au(111). Scanning tunneling microscopy and noncontact atomic force microscopy describe the thermal-activated intra- and intermolecular oxidative ring closure reactions as well as the controlled tip-induced hydrogen dissociation from the porphyrinoid units. In addition, scanning tunneling spectroscopy measurements, complemented by computational investigations, reveal the open-shell character, that is, the antiferromagnetic singlet ground state (S = 0) of the formed polymers, characterized by singlet-triplet inelastic excitations observed between spins of adjacent porphyrinoid units. Our approach sheds light on the crucial relevance of the π-conjugation in the correlations between spins, while expanding the on-surface synthesis toolbox and opening avenues toward the synthesis of innovative functional nanomaterials with prospects in carbon-based spintronics.
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Affiliation(s)
- Kalyan Biswas
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, Madrid 28049, Spain
| | - Maxence Urbani
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, Madrid 28049, Spain
| | - Ana Sánchez-Grande
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, Madrid 28049, Spain
| | - Diego Soler-Polo
- Institute of Physics of the Czech Academy of Science, Praha 162 00, Czech Republic
| | - Koen Lauwaet
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, Madrid 28049, Spain
| | - Adam Matěj
- Institute of Physics of the Czech Academy of Science, Praha 162 00, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Olomouc 783 71, Czech Republic
| | - Pingo Mutombo
- Institute of Physics of the Czech Academy of Science, Praha 162 00, Czech Republic
| | - Libor Veis
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague 182 00, Czech Republic
| | - Jiri Brabec
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague 182 00, Czech Republic
| | - Katarzyna Pernal
- Institute of Physics, Lodz University of Technology, Lodz 90-924, Poland
| | - José M Gallego
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, Madrid 28049, Spain
| | - Rodolfo Miranda
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, Madrid 28049, Spain.,Departamento de Física de La Materia Condensada, Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - David Écija
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, Madrid 28049, Spain
| | - Pavel Jelínek
- Institute of Physics of the Czech Academy of Science, Praha 162 00, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Olomouc 783 71, Czech Republic
| | - Tomás Torres
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, Madrid 28049, Spain.,Departamento de Química Orgánica and Institute for Advanced Research in Chemistry (IAdChem), Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - José I Urgel
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, Madrid 28049, Spain
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35
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Sun Q, Mateo LM, Robles R, Ruffieux P, Bottari G, Torres T, Fasel R, Lorente N. Magnetic Interplay between π-Electrons of Open-Shell Porphyrins and d-Electrons of Their Central Transition Metal Ions. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2105906. [PMID: 35302718 PMCID: PMC9259720 DOI: 10.1002/advs.202105906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/09/2022] [Indexed: 06/14/2023]
Abstract
Magnetism is typically associated with d- or f-block elements, but can also appear in organic molecules with unpaired π-electrons. This has considerably boosted the interest in such organic materials with large potential for spintronics and quantum applications. While several materials showing either d/f or π-electron magnetism have been synthesized, the combination of both features within the same structure has only scarcely been reported. Open-shell porphyrins (Pors) incorporating d-block transition metal ions represent an ideal platform for the realization of such architectures. Herein, the preparation of a series of open-shell, π-extended Pors that contain magnetically active metal ions (i.e., CuII , CoII , and FeII ) through a combination of in-solution and on-surface synthesis is reported. A detailed study of the magnetic interplay between π- and d-electrons in these metalloPors has been performed by scanning probe methods and density functional theory calculations. For the Cu and FePors, ferromagnetically coupled π-electrons are determined to be delocalized over the Por edges. For the CoPor, the authors find a Kondo resonance resulting from the singly occupied CoII dz 2 orbital to dominate the magnetic fingerprint. The Fe derivative exhibits the highest magnetization of 3.67 μB (S≈2) and an exchange coupling of 16 meV between the π-electrons and the Fe d-states.
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Affiliation(s)
- Qiang Sun
- nanotech@surfaces LaboratoryEmpa ‐ Swiss Federal Laboratories for Materials Science and TechnologyDübendorf8600Switzerland
- Materials Genome InstituteShanghai UniversityShanghai200444China
| | - Luis M. Mateo
- Departamento de Química OrgánicaUniversidad Autónoma de MadridMadrid28049Spain
- IMDEA‐NanocienciaCampus de CantoblancoMadrid28049Spain
| | - Roberto Robles
- Centro de Física de Materiales CFM/MPC (CSIC‐UPV/EHU)Paseo de Manuel de Lardizabal 5Donostia‐San Sebastián20018Spain
| | - Pascal Ruffieux
- nanotech@surfaces LaboratoryEmpa ‐ Swiss Federal Laboratories for Materials Science and TechnologyDübendorf8600Switzerland
| | - Giovanni Bottari
- Departamento de Química OrgánicaUniversidad Autónoma de MadridMadrid28049Spain
- IMDEA‐NanocienciaCampus de CantoblancoMadrid28049Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem)Universidad Autónoma de MadridMadrid28049Spain
| | - Tomás Torres
- Departamento de Química OrgánicaUniversidad Autónoma de MadridMadrid28049Spain
- IMDEA‐NanocienciaCampus de CantoblancoMadrid28049Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem)Universidad Autónoma de MadridMadrid28049Spain
| | - Roman Fasel
- nanotech@surfaces LaboratoryEmpa ‐ Swiss Federal Laboratories for Materials Science and TechnologyDübendorf8600Switzerland
- Department of ChemistryBiochemistry and Pharmaceutical SciencesUniversity of BernBern3012Switzerland
| | - Nicolás Lorente
- Centro de Física de Materiales CFM/MPC (CSIC‐UPV/EHU)Paseo de Manuel de Lardizabal 5Donostia‐San Sebastián20018Spain
- Donostia International Physics Center (DIPC)Donostia‐San Sebastián20018Spain
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36
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Biswas K, Urgel JI, Ajayakumar MR, Ma J, Sánchez-Grande A, Edalatmanesh S, Lauwaet K, Mutombo P, Gallego JM, Miranda R, Jelínek P, Feng X, Écija D. Synthesis and Characterization of peri-Heptacene on a Metallic Surface. Angew Chem Int Ed Engl 2022; 61:e202114983. [PMID: 35170842 DOI: 10.1002/anie.202114983] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Indexed: 11/09/2022]
Abstract
The synthesis of long n-peri-acenes (n-PAs) is challenging as a result of their inherent open-shell radical character, which arises from the presence of parallel zigzag edges beyond a certain n value. They are considered as π-electron model systems to study magnetism in graphene nanostructures; being potential candidates in the fabrication of optoelectronic and spintronic devices. Here, we report the on-surface formation of the largest pristine member of the n-PA family, i.e. peri-heptacene (n=7, 7-PA), obtained on an Au(111) substrate under ultra-high vacuum conditions. Our high-resolution scanning tunneling microscopy investigations, complemented by theoretical simulations, provide insight into the chemical structure of this previously elusive compound. In addition, scanning tunneling spectroscopy reveals the antiferromagnetic open-shell singlet ground state of 7-PA, exhibiting singlet-triplet spin-flip inelastic excitations with an effective exchange coupling (Jeff ) of 49 meV.
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Affiliation(s)
- Kalyan Biswas
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
| | - José I Urgel
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
| | - M R Ajayakumar
- Center for Advancing Electronics and Faculty of Chemistry and Food Chemistry, Technical University of Dresden, 01062, Dresden, Germany
| | - Ji Ma
- Center for Advancing Electronics and Faculty of Chemistry and Food Chemistry, Technical University of Dresden, 01062, Dresden, Germany
| | - Ana Sánchez-Grande
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Shayan Edalatmanesh
- Institute of Physics of the Czech Academy of Science, 16253, Praha, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Palacký University Olomouc, 771 46, Olomouc, Czech Republic
| | - Koen Lauwaet
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Pingo Mutombo
- Institute of Physics of the Czech Academy of Science, 16253, Praha, Czech Republic
| | - José M Gallego
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049, Madrid, Spain
| | - Rodolfo Miranda
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain.,Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Pavel Jelínek
- Institute of Physics of the Czech Academy of Science, 16253, Praha, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Palacký University Olomouc, 771 46, Olomouc, Czech Republic
| | - Xinliang Feng
- Center for Advancing Electronics and Faculty of Chemistry and Food Chemistry, Technical University of Dresden, 01062, Dresden, Germany
| | - David Écija
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
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37
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Biswas K, Urgel JI, Ajayakumar MR, Ma J, Sánchez‐Grande A, Edalatmanesh S, Lauwaet K, Mutombo P, Gallego JM, Miranda R, Jelínek P, Feng X, Écija D. Synthesis and Characterization of
peri
‐Heptacene on a Metallic Surface. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202114983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Kalyan Biswas
- IMDEA Nanoscience C/ Faraday 9, Campus de Cantoblanco 28049 Madrid Spain
| | - José I. Urgel
- IMDEA Nanoscience C/ Faraday 9, Campus de Cantoblanco 28049 Madrid Spain
| | - M. R. Ajayakumar
- Center for Advancing Electronics and Faculty of Chemistry and Food Chemistry Technical University of Dresden 01062 Dresden Germany
| | - Ji Ma
- Center for Advancing Electronics and Faculty of Chemistry and Food Chemistry Technical University of Dresden 01062 Dresden Germany
| | - Ana Sánchez‐Grande
- IMDEA Nanoscience C/ Faraday 9, Campus de Cantoblanco 28049 Madrid Spain
| | - Shayan Edalatmanesh
- Institute of Physics of the Czech Academy of Science 16253 Praha Czech Republic
- Regional Centre of Advanced Technologies and Materials Palacký University Olomouc 771 46 Olomouc Czech Republic
| | - Koen Lauwaet
- IMDEA Nanoscience C/ Faraday 9, Campus de Cantoblanco 28049 Madrid Spain
| | - Pingo Mutombo
- Institute of Physics of the Czech Academy of Science 16253 Praha Czech Republic
| | - José M. Gallego
- Instituto de Ciencia de Materiales de Madrid CSIC 28049 Madrid Spain
| | - Rodolfo Miranda
- IMDEA Nanoscience C/ Faraday 9, Campus de Cantoblanco 28049 Madrid Spain
- Departamento de Física de la Materia Condensada Universidad Autónoma de Madrid 28049 Madrid Spain
| | - Pavel Jelínek
- Institute of Physics of the Czech Academy of Science 16253 Praha Czech Republic
- Regional Centre of Advanced Technologies and Materials Palacký University Olomouc 771 46 Olomouc Czech Republic
| | - Xinliang Feng
- Center for Advancing Electronics and Faculty of Chemistry and Food Chemistry Technical University of Dresden 01062 Dresden Germany
| | - David Écija
- IMDEA Nanoscience C/ Faraday 9, Campus de Cantoblanco 28049 Madrid Spain
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38
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On-surface synthesis of triangulene trimers via dehydration reaction. Nat Commun 2022; 13:1705. [PMID: 35361812 PMCID: PMC8971457 DOI: 10.1038/s41467-022-29371-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 03/04/2022] [Indexed: 11/08/2022] Open
Abstract
Triangulene and its homologues are of considerable interest for molecular spintronics due to their high-spin ground states as well as the potential for constructing high spin frameworks. Realizing triangulene-based high-spin system on surface is challenging but of particular importance for understanding π-electron magnetism. Here, we report two approaches to generate triangulene trimers on Au(111) by using surface-assisted dehydration and alkyne trimerization, respectively. We find that the developed dehydration reaction shows much higher chemoselectivity thus resulting in significant promotion of product yield compared to that using alkyne trimerization approach, through cutting the side reaction path. Combined with spin-polarized density functional theory calculations, scanning tunneling spectroscopy measurements identify the septuple (S = 3) high-spin ground state and quantify the collective ferromagnetic interaction among three triangulene units. Our results demonstrate the approaches to fabricate high-quality triangulene-based high spin systems and understand their magnetic interactions, which are essential for realizing carbon-based spintronic devices.
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39
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Wang T, Berdonces-Layunta A, Friedrich N, Vilas-Varela M, Calupitan JP, Pascual JI, Peña D, Casanova D, Corso M, de Oteyza DG. Aza-Triangulene: On-Surface Synthesis and Electronic and Magnetic Properties. J Am Chem Soc 2022; 144:4522-4529. [PMID: 35254059 PMCID: PMC8931755 DOI: 10.1021/jacs.1c12618] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
![]()
Nitrogen
heteroatom doping into a triangulene molecule allows tuning
its magnetic state. However, the synthesis of the nitrogen-doped triangulene
(aza-triangulene) has been challenging. Herein, we report the successful
synthesis of aza-triangulene on the Au(111) and Ag(111) surfaces,
along with their characterizations by scanning tunneling microscopy
and spectroscopy in combination with density functional theory (DFT)
calculations. Aza-triangulenes were obtained by reducing ketone-substituted
precursors. Exposure to atomic hydrogen followed by thermal annealing
and, when necessary, manipulations with the scanning probe afforded
the target product. We demonstrate that on Au(111), aza-triangulene
donates an electron to the substrate and exhibits an open-shell triplet
ground state. This is derived from the different Kondo resonances
of the final aza-triangulene product and a series of intermediates
on Au(111). Experimentally mapped molecular orbitals match with DFT-calculated
counterparts for a positively charged aza-triangulene. In contrast,
aza-triangulene on Ag(111) receives an extra electron from the substrate
and displays a closed-shell character. Our study reveals the electronic
properties of aza-triangulene on different metal surfaces and offers
an approach for the fabrication of new hydrocarbon structures, including
reactive open-shell molecules.
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Affiliation(s)
- Tao Wang
- Donostia International Physics Center, 20018 San Sebastián, Spain
- Centro de Fisica de Materiales CFM/MPC, CSIC-UPV/EHU, 20018 San Sebastián, Spain
| | - Alejandro Berdonces-Layunta
- Donostia International Physics Center, 20018 San Sebastián, Spain
- Centro de Fisica de Materiales CFM/MPC, CSIC-UPV/EHU, 20018 San Sebastián, Spain
| | | | - Manuel Vilas-Varela
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | | | - Jose Ignacio Pascual
- CIC NanoGUNE BRTA, 20018 San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48009 Bilbao, Spain
| | - Diego Peña
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - David Casanova
- Donostia International Physics Center, 20018 San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48009 Bilbao, Spain
| | - Martina Corso
- Donostia International Physics Center, 20018 San Sebastián, Spain
- Centro de Fisica de Materiales CFM/MPC, CSIC-UPV/EHU, 20018 San Sebastián, Spain
| | - Dimas G. de Oteyza
- Donostia International Physics Center, 20018 San Sebastián, Spain
- Centro de Fisica de Materiales CFM/MPC, CSIC-UPV/EHU, 20018 San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48009 Bilbao, Spain
- Nanomaterials and Nanotechnology Research Center (CINN), CSIC-UNIOVI-PA; 33940 El Entrego, Spain
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40
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Eimre K, Urgel JI, Hayashi H, Di Giovannantonio M, Ruffieux P, Sato S, Otomo S, Chan YS, Aratani N, Passerone D, Gröning O, Yamada H, Fasel R, Pignedoli CA. On-surface synthesis and characterization of nitrogen-substituted undecacenes. Nat Commun 2022; 13:511. [PMID: 35082284 PMCID: PMC8791976 DOI: 10.1038/s41467-022-27961-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 12/17/2021] [Indexed: 02/05/2023] Open
Abstract
Heteroatom substitution in acenes allows tailoring of their remarkable electronic properties, expected to include spin-polarization and magnetism for larger members of the acene family. Here, we present a strategy for the on-surface synthesis of three undecacene analogs substituted with four nitrogen atoms on an Au(111) substrate, by employing specifically designed diethano-bridged precursors. A similarly designed precursor is used to synthesize the pristine undecacene molecule. By comparing experimental features of scanning probe microscopy with ab initio simulations, we demonstrate that the ground state of the synthesized tetraazaundecacene has considerable open-shell character on Au(111). Additionally, we demonstrate that the electronegative nitrogen atoms induce a considerable shift in energy level alignment compared to the pristine undecacene, and that the introduction of hydro-aza groups causes local anti-aromaticity in the synthesized compounds. Our work provides access to the precise fabrication of nitrogen-substituted acenes and their analogs, potential building-blocks of organic electronics and spintronics, and a rich playground to explore π-electron correlation.
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Affiliation(s)
- Kristjan Eimre
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland.
| | - José I Urgel
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland.
- IMDEA Nanoscience, C/ Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain.
| | - Hironobu Hayashi
- Division of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma, 630-0192, Japan
| | - Marco Di Giovannantonio
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland
- Istituto di Struttura della Materia-CNR (ISM-CNR), via Fosso del Cavaliere 100, 00133, Roma, Italy
| | - Pascal Ruffieux
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Shizuka Sato
- Division of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma, 630-0192, Japan
| | - Satoru Otomo
- Division of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma, 630-0192, Japan
| | - Yee Seng Chan
- Division of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma, 630-0192, Japan
| | - Naoki Aratani
- Division of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma, 630-0192, Japan
| | - Daniele Passerone
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Oliver Gröning
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Hiroko Yamada
- Division of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma, 630-0192, Japan.
| | - Roman Fasel
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland.
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012, Bern, Switzerland.
| | - Carlo A Pignedoli
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland.
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41
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Wang T, Sanz S, Castro-Esteban J, Lawrence J, Berdonces-Layunta A, Mohammed MSG, Vilas-Varela M, Corso M, Peña D, Frederiksen T, de Oteyza DG. Magnetic Interactions Between Radical Pairs in Chiral Graphene Nanoribbons. NANO LETTERS 2022; 22:164-171. [PMID: 34936370 DOI: 10.1021/acs.nanolett.1c03578] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Open-shell graphene nanoribbons have become promising candidates for future applications, including quantum technologies. Here, we characterize magnetic states hosted by chiral graphene nanoribbons (chGNRs). The substitution of a hydrogen atom at the chGNR edge by a ketone effectively adds one pz electron to the π-electron network, producing an unpaired π-radical. A similar scenario occurs for regular ketone-functionalized chGNRs in which one ketone is missing. Two such radical states can interact via exchange coupling, and we study those interactions as a function of their relative position, which includes a remarkable dependence on the chirality, as well as on the nature of the surrounding ribbon, that is, with or without ketone functionalization. Besides, we determine the parameters whereby this type of system with oxygen heteroatoms can be adequately described within the widely used mean-field Hubbard model. Altogether, we provide insight to both theoretically model and devise GNR-based nanostructures with tunable magnetic properties.
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Affiliation(s)
- Tao Wang
- Donostia International Physics Center, 20018 San Sebastián, Spain
- Centro de Fisica de Materiales CFM/MPC, CSIC-UPV/EHU, 20018 San Sebastián, Spain
| | - Sofia Sanz
- Donostia International Physics Center, 20018 San Sebastián, Spain
| | - Jesús Castro-Esteban
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - James Lawrence
- Donostia International Physics Center, 20018 San Sebastián, Spain
- Centro de Fisica de Materiales CFM/MPC, CSIC-UPV/EHU, 20018 San Sebastián, Spain
| | - Alejandro Berdonces-Layunta
- Donostia International Physics Center, 20018 San Sebastián, Spain
- Centro de Fisica de Materiales CFM/MPC, CSIC-UPV/EHU, 20018 San Sebastián, Spain
| | - Mohammed S G Mohammed
- Donostia International Physics Center, 20018 San Sebastián, Spain
- Centro de Fisica de Materiales CFM/MPC, CSIC-UPV/EHU, 20018 San Sebastián, Spain
| | - Manuel Vilas-Varela
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Martina Corso
- Donostia International Physics Center, 20018 San Sebastián, Spain
- Centro de Fisica de Materiales CFM/MPC, CSIC-UPV/EHU, 20018 San Sebastián, Spain
| | - Diego Peña
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Thomas Frederiksen
- Donostia International Physics Center, 20018 San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Dimas G de Oteyza
- Donostia International Physics Center, 20018 San Sebastián, Spain
- Centro de Fisica de Materiales CFM/MPC, CSIC-UPV/EHU, 20018 San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
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42
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Biswas K, Yang L, Ma J, Sánchez-Grande A, Chen Q, Lauwaet K, Gallego JM, Miranda R, Écija D, Jelínek P, Feng X, Urgel JI. Defect-Induced π-Magnetism into Non-Benzenoid Nanographenes. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:224. [PMID: 35055243 PMCID: PMC8780648 DOI: 10.3390/nano12020224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/04/2022] [Accepted: 01/06/2022] [Indexed: 02/06/2023]
Abstract
The synthesis of nanographenes (NGs) with open-shell ground states have recently attained increasing attention in view of their interesting physicochemical properties and great prospects in manifold applications as suitable materials within the rising field of carbon-based magnetism. A potential route to induce magnetism in NGs is the introduction of structural defects, for instance non-benzenoid rings, in their honeycomb lattice. Here, we report the on-surface synthesis of three open-shell non-benzenoid NGs (A1, A2 and A3) on the Au(111) surface. A1 and A2 contain two five- and one seven-membered rings within their benzenoid backbone, while A3 incorporates one five-membered ring. Their structures and electronic properties have been investigated by means of scanning tunneling microscopy, noncontact atomic force microscopy and scanning tunneling spectroscopy complemented with theoretical calculations. Our results provide access to open-shell NGs with a combination of non-benzenoid topologies previously precluded by conventional synthetic procedures.
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Affiliation(s)
- Kalyan Biswas
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049 Madrid, Spain; (K.B.); (A.S.-G.); (K.L.); (R.M.)
| | - Lin Yang
- Center for Advancing Electronics, Faculty of Chemistry and Food Chemistry, Technical University of Dresden, 01062 Dresden, Germany; (L.Y.); (X.F.)
| | - Ji Ma
- Center for Advancing Electronics, Faculty of Chemistry and Food Chemistry, Technical University of Dresden, 01062 Dresden, Germany; (L.Y.); (X.F.)
| | - Ana Sánchez-Grande
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049 Madrid, Spain; (K.B.); (A.S.-G.); (K.L.); (R.M.)
| | - Qifan Chen
- Institute of Physics of the Czech Academy of Science, CZ-16253 Praha, Czech Republic;
| | - Koen Lauwaet
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049 Madrid, Spain; (K.B.); (A.S.-G.); (K.L.); (R.M.)
| | - José M. Gallego
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain;
| | - Rodolfo Miranda
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049 Madrid, Spain; (K.B.); (A.S.-G.); (K.L.); (R.M.)
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - David Écija
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049 Madrid, Spain; (K.B.); (A.S.-G.); (K.L.); (R.M.)
| | - Pavel Jelínek
- Institute of Physics of the Czech Academy of Science, CZ-16253 Praha, Czech Republic;
- Regional Centre of Advanced Technologies and Materials, Palacký University Olomouc, CZ-77146 Olomouc, Czech Republic
| | - Xinliang Feng
- Center for Advancing Electronics, Faculty of Chemistry and Food Chemistry, Technical University of Dresden, 01062 Dresden, Germany; (L.Y.); (X.F.)
| | - José I. Urgel
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049 Madrid, Spain; (K.B.); (A.S.-G.); (K.L.); (R.M.)
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43
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Wang S, Nishiuchi T, Pignedoli CA, Yao X, Di Giovannantonio M, Zhao Y, Narita A, Feng X, Müllen K, Ruffieux P, Fasel R. Steering on-surface reactions through molecular steric hindrance and molecule-substrate van der Waals interactions. QUANTUM FRONTIERS 2022; 1:23. [PMID: 36619715 PMCID: PMC9809985 DOI: 10.1007/s44214-022-00023-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 11/19/2022] [Accepted: 11/21/2022] [Indexed: 12/13/2022]
Abstract
On-surface synthesis is a rapidly developing field involving chemical reactions on well-defined solid surfaces to access synthesis of low-dimensional organic nanostructures which cannot be achieved via traditional solution chemistry. On-surface reactions critically depend on a high degree of chemoselectivity in order to achieve an optimum balance between target structure and possible side products. Here, we demonstrate synthesis of graphene nanoribbons with a large unit cell based on steric hindrance-induced complete chemoselectivity as revealed by scanning probe microscopy measurements and density functional theory calculations. Our results disclose that combined molecule-substrate van der Waals interactions and intermolecular steric hindrance promote a selective aryl-aryl coupling, giving rise to high-quality uniform graphene nanostructures. The established coupling strategy has been used to synthesize two types of graphene nanoribbons with different edge topologies inducing a pronounced variation of the electronic energy gaps. The demonstrated chemoselectivity is representative for n-anthryl precursor molecules and may be further exploited to synthesize graphene nanoribbons with novel electronic, topological and magnetic properties with implications for electronic and spintronic applications. Supplementary Information The online version contains supplementary material available at 10.1007/s44214-022-00023-9.
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Affiliation(s)
- Shiyong Wang
- grid.7354.50000 0001 2331 3059Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland ,grid.16821.3c0000 0004 0368 8293Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Tomohiko Nishiuchi
- grid.419547.a0000 0001 1010 1663Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany ,grid.136593.b0000 0004 0373 3971Department of Chemistry, Graduate School of Science, Osaka University, Suita, 560-0043 Japan
| | - Carlo A. Pignedoli
- grid.7354.50000 0001 2331 3059Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - Xuelin Yao
- grid.419547.a0000 0001 1010 1663Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Marco Di Giovannantonio
- grid.7354.50000 0001 2331 3059Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland ,grid.5326.20000 0001 1940 4177Present Address: Istituto di Struttura della Materia—CNR (ISM-CNR), via Fosso del Cavaliere 100, Roma, 00133 Italy
| | - Yan Zhao
- grid.16821.3c0000 0004 0368 8293Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Akimitsu Narita
- grid.419547.a0000 0001 1010 1663Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Xinliang Feng
- grid.4488.00000 0001 2111 7257Department of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstrasse 4, 01062 Dresden, Germany
| | - Klaus Müllen
- grid.419547.a0000 0001 1010 1663Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Pascal Ruffieux
- grid.7354.50000 0001 2331 3059Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - Roman Fasel
- grid.7354.50000 0001 2331 3059Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland ,grid.5734.50000 0001 0726 5157Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
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44
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Spin State Switching in Heptauthrene Nanostructure by Electric Field: Computational Study. Int J Mol Sci 2021; 22:ijms222413364. [PMID: 34948161 PMCID: PMC8705984 DOI: 10.3390/ijms222413364] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 11/26/2021] [Accepted: 11/29/2021] [Indexed: 11/23/2022] Open
Abstract
Recent experimental studies proved the presence of the triplet spin state in atomically precise heptauthrene nanostructure of nanographene type (composed of two interconnected triangles with zigzag edge). In the paper, we report the computational study predicting the possibility of controlling this spin state with an external in-plane electric field by causing the spin switching. We construct and discuss the ground state magnetic phase diagram involving S=1 (triplet) state, S=0 antiferromagnetic state and non-magnetic state and predict the switching possibility with the critical electric field of the order of 0.1 V/Å. We discuss the spin distribution across the nanostructure, finding its concentration along the longest zigzag edge. To model our system of interest, we use the mean-field Hubbard Hamiltonian, taking into account the in-plane external electric field as well as the in-plane magnetic field (in a form of the exchange field from the substrate). We also assess the effect of uniaxial strain on the magnetic phase diagram.
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45
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Liu X, Qin X, Li X, Ding Z, Li X, Hu W, Yang J. Designing Two-Dimensional Versatile Room-Temperature Ferromagnets via Assembling Large-Scale Magnetic Quantum Dots. NANO LETTERS 2021; 21:9816-9823. [PMID: 34761940 DOI: 10.1021/acs.nanolett.1c03814] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Two-dimensional (2D) ferromagnets possess astonishing potential in new-concept spintronics. However, most of the reported intrinsic 2D ferromagnets show a low Curie temperature far below room temperature. Here, we propose a series of 2D magnetic covalent and metal organic frameworks (COFs/MOFs) by assembling triangular zigzag graphene quantum dots (TZGDs) with various linkages, involving small-sized TZGDs, nonmetal atoms, magnetic metal atoms, and molecules. Upon first-principles calculations, we demonstrate 2D magnetic semiconductors with an enhanced Curie temperature of up to 472 K can be realized through the strong p(d)-p direct exchange interaction between TZGDs and linkages. Particularly, the TZGD size hardly affects the Curie temperature, whereas linkages can modulate the Curie temperature significantly. The TZGD size and linkages can regulate the electronic and magnetic properties of TZGD-based 2D ferromagnets. Our results confirm the possibility of designing 2D ferromagnets based on TZGDs and motivate the research of 2D ferromagnets on magnetic quantum dots and molecular magnets.
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Affiliation(s)
- Xiaofeng Liu
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xinming Qin
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiangyang Li
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zijing Ding
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xingxing Li
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Wei Hu
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jinlong Yang
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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46
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Hieulle J, Castro S, Friedrich N, Vegliante A, Lara FR, Sanz S, Rey D, Corso M, Frederiksen T, Pascual JI, Peña D. On-Surface Synthesis and Collective Spin Excitations of a Triangulene-Based Nanostar. Angew Chem Int Ed Engl 2021; 60:25224-25229. [PMID: 34647398 PMCID: PMC9292598 DOI: 10.1002/anie.202108301] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Indexed: 12/02/2022]
Abstract
Triangulene nanographenes are open‐shell molecules with predicted high spin state due to the frustration of their conjugated network. Their long‐sought synthesis became recently possible over a metal surface. Here, we present a macrocycle formed by six [3]triangulenes, which was obtained by combining the solution synthesis of a dimethylphenyl‐anthracene cyclic hexamer and the on‐surface cyclodehydrogenation of this precursor over a gold substrate. The resulting triangulene nanostar exhibits a collective spin state generated by the interaction of its 12 unpaired π‐electrons along the conjugated lattice, corresponding to the antiferromagnetic ordering of six S=1 sites (one per triangulene unit). Inelastic electron tunneling spectroscopy resolved three spin excitations connecting the singlet ground state with triplet states. The nanostar behaves close to predictions from the Heisenberg model of an S=1 spin ring, representing a unique system to test collective spin modes in cyclic systems.
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Affiliation(s)
| | - Silvia Castro
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782-, Santiago de Compostela, Spain
| | | | | | - Francisco Romero Lara
- CIC nanoGUNE-BRTA, 20018, Donostia-San Sebastián, Spain.,Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center, 20018, Donostia-San Sebastián, Spain
| | - Sofía Sanz
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastián, Spain
| | - Dulce Rey
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782-, Santiago de Compostela, Spain
| | - Martina Corso
- Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center, 20018, Donostia-San Sebastián, Spain.,Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastián, Spain
| | - Thomas Frederiksen
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastián, Spain.,Ikerbasque, Basque Foundation for Science, 48013, Bilbao, Spain
| | - Jose Ignacio Pascual
- CIC nanoGUNE-BRTA, 20018, Donostia-San Sebastián, Spain.,Ikerbasque, Basque Foundation for Science, 48013, Bilbao, Spain
| | - Diego Peña
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782-, Santiago de Compostela, Spain
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47
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Hieulle J, Castro S, Friedrich N, Vegliante A, Lara FR, Sanz S, Rey D, Corso M, Frederiksen T, Pascual JI, Peña D. On‐Surface Synthesis and Collective Spin Excitations of a Triangulene‐Based Nanostar. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202108301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Silvia Castro
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica Universidade de Santiago de Compostela 15782- Santiago de Compostela Spain
| | | | | | - Francisco Romero Lara
- CIC nanoGUNE-BRTA 20018 Donostia-San Sebastián Spain
- Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center 20018 Donostia-San Sebastián Spain
| | - Sofía Sanz
- Donostia International Physics Center (DIPC) 20018 Donostia-San Sebastián Spain
| | - Dulce Rey
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica Universidade de Santiago de Compostela 15782- Santiago de Compostela Spain
| | - Martina Corso
- Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center 20018 Donostia-San Sebastián Spain
- Donostia International Physics Center (DIPC) 20018 Donostia-San Sebastián Spain
| | - Thomas Frederiksen
- Donostia International Physics Center (DIPC) 20018 Donostia-San Sebastián Spain
- Ikerbasque Basque Foundation for Science 48013 Bilbao Spain
| | - Jose Ignacio Pascual
- CIC nanoGUNE-BRTA 20018 Donostia-San Sebastián Spain
- Ikerbasque Basque Foundation for Science 48013 Bilbao Spain
| | - Diego Peña
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica Universidade de Santiago de Compostela 15782- Santiago de Compostela Spain
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48
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Peng X, Mahalingam H, Dong S, Mutombo P, Su J, Telychko M, Song S, Lyu P, Ng PW, Wu J, Jelínek P, Chi C, Rodin A, Lu J. Visualizing designer quantum states in stable macrocycle quantum corrals. Nat Commun 2021; 12:5895. [PMID: 34625542 PMCID: PMC8501084 DOI: 10.1038/s41467-021-26198-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 09/20/2021] [Indexed: 02/08/2023] Open
Abstract
Creating atomically precise quantum architectures with high digital fidelity and desired quantum states is an important goal in a new era of quantum technology. The strategy of creating these quantum nanostructures mainly relies on atom-by-atom, molecule-by-molecule manipulation or molecular assembly through non-covalent interactions, which thus lack sufficient chemical robustness required for on-chip quantum device operation at elevated temperature. Here, we report a bottom-up synthesis of covalently linked organic quantum corrals (OQCs) with atomic precision to induce the formation of topology-controlled quantum resonance states, arising from a collective interference of scattered electron waves inside the quantum nanocavities. Individual OQCs host a series of atomic orbital-like resonance states whose orbital hybridization into artificial homo-diatomic and hetero-diatomic molecular-like resonance states can be constructed in Cassini oval-shaped OQCs with desired topologies corroborated by joint ab initio and analytic calculations. Our studies open up a new avenue to fabricate covalently linked large-sized OQCs with atomic precision to engineer desired quantum states with high chemical robustness and digital fidelity for future practical applications.
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Affiliation(s)
- Xinnan Peng
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | | | - Shaoqiang Dong
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | - Pingo Mutombo
- Institute of Physics, Czech Academy of Sciences, Prague, 16200, Czech Republic
| | - Jie Su
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | - Mykola Telychko
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | - Shaotang Song
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | - Pin Lyu
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | - Pei Wen Ng
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | - Jishan Wu
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | - Pavel Jelínek
- Institute of Physics, Czech Academy of Sciences, Prague, 16200, Czech Republic.
- Regional Centre of Advanced Technologies and Materials, Palacký University, Olomouc, 78371, Czech Republic.
| | - Chunyan Chi
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore.
| | - Aleksandr Rodin
- Yale-NUS College, 16 College Avenue West, Singapore, 138527, Singapore.
- Centre for Advanced 2D Materials (CA2DM), National University of Singapore, Singapore, 117543, Singapore.
| | - Jiong Lu
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore.
- Centre for Advanced 2D Materials (CA2DM), National University of Singapore, Singapore, 117543, Singapore.
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49
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Mishra S, Catarina G, Wu F, Ortiz R, Jacob D, Eimre K, Ma J, Pignedoli CA, Feng X, Ruffieux P, Fernández-Rossier J, Fasel R. Observation of fractional edge excitations in nanographene spin chains. Nature 2021; 598:287-292. [PMID: 34645998 DOI: 10.1038/s41586-021-03842-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/20/2021] [Indexed: 11/09/2022]
Abstract
Fractionalization is a phenomenon in which strong interactions in a quantum system drive the emergence of excitations with quantum numbers that are absent in the building blocks. Outstanding examples are excitations with charge e/3 in the fractional quantum Hall effect1,2, solitons in one-dimensional conducting polymers3,4 and Majorana states in topological superconductors5. Fractionalization is also predicted to manifest itself in low-dimensional quantum magnets, such as one-dimensional antiferromagnetic S = 1 chains. The fundamental features of this system are gapped excitations in the bulk6 and, remarkably, S = 1/2 edge states at the chain termini7-9, leading to a four-fold degenerate ground state that reflects the underlying symmetry-protected topological order10,11. Here, we use on-surface synthesis12 to fabricate one-dimensional spin chains that contain the S = 1 polycyclic aromatic hydrocarbon triangulene as the building block. Using scanning tunnelling microscopy and spectroscopy at 4.5 K, we probe length-dependent magnetic excitations at the atomic scale in both open-ended and cyclic spin chains, and directly observe gapped spin excitations and fractional edge states therein. Exact diagonalization calculations provide conclusive evidence that the spin chains are described by the S = 1 bilinear-biquadratic Hamiltonian in the Haldane symmetry-protected topological phase. Our results open a bottom-up approach to study strongly correlated phases in purely organic materials, with the potential for the realization of measurement-based quantum computation13.
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Affiliation(s)
- Shantanu Mishra
- Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland.,IBM Research-Zurich, Rüschlikon, Switzerland
| | - Gonçalo Catarina
- International Iberian Nanotechnology Laboratory, Braga, Portugal.,University of Alicante, Sant Vicent del Raspeig, Spain
| | - Fupeng Wu
- Technical University of Dresden, Dresden, Germany
| | - Ricardo Ortiz
- University of Alicante, Sant Vicent del Raspeig, Spain
| | - David Jacob
- University of the Basque Country, San Sebastián, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Kristjan Eimre
- Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
| | - Ji Ma
- Technical University of Dresden, Dresden, Germany
| | - Carlo A Pignedoli
- Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
| | - Xinliang Feng
- Technical University of Dresden, Dresden, Germany. .,Max Planck Institute of Microstructure Physics, Halle, Germany.
| | - Pascal Ruffieux
- Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland.
| | | | - Roman Fasel
- Empa-Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland.,University of Bern, Bern, Switzerland
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Li J, Sanz S, Merino-Díez N, Vilas-Varela M, Garcia-Lekue A, Corso M, de Oteyza DG, Frederiksen T, Peña D, Pascual JI. Topological phase transition in chiral graphene nanoribbons: from edge bands to end states. Nat Commun 2021; 12:5538. [PMID: 34545075 PMCID: PMC8452617 DOI: 10.1038/s41467-021-25688-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 08/20/2021] [Indexed: 02/08/2023] Open
Abstract
Precise control over the size and shape of graphene nanostructures allows engineering spin-polarized edge and topological states, representing a novel source of non-conventional π-magnetism with promising applications in quantum spintronics. A prerequisite for their emergence is the existence of robust gapped phases, which are difficult to find in extended graphene systems. Here we show that semi-metallic chiral GNRs (chGNRs) narrowed down to nanometer widths undergo a topological phase transition. We fabricated atomically precise chGNRs of different chirality and size by on surface synthesis using predesigned molecular precursors. Combining scanning tunneling microscopy (STM) measurements and theory simulations, we follow the evolution of topological properties and bulk band gap depending on the width, length, and chirality of chGNRs. Our findings represent a new platform for producing topologically protected spin states and demonstrate the potential of connecting chiral edge and defect structure with band engineering.
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Affiliation(s)
- Jingcheng Li
- grid.424265.30000 0004 1761 1166CIC nanoGUNE-BRTA, Donostia-San Sebastián, Spain ,Centro de Física de Materiales MPC (CSIC-UPV/EHU), Donostia-San Sebastián, Spain ,grid.12981.330000 0001 2360 039XPresent Address: School of Physics, Sun Yat-sen University, Guangzhou, China
| | - Sofia Sanz
- grid.452382.a0000 0004 1768 3100Donostia International Physics Center (DIPC), Donostia-San Sebastián, Spain
| | - Nestor Merino-Díez
- grid.424265.30000 0004 1761 1166CIC nanoGUNE-BRTA, Donostia-San Sebastián, Spain ,grid.452382.a0000 0004 1768 3100Donostia International Physics Center (DIPC), Donostia-San Sebastián, Spain
| | - Manuel Vilas-Varela
- grid.11794.3a0000000109410645Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Aran Garcia-Lekue
- grid.452382.a0000 0004 1768 3100Donostia International Physics Center (DIPC), Donostia-San Sebastián, Spain ,grid.424810.b0000 0004 0467 2314Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Martina Corso
- Centro de Física de Materiales MPC (CSIC-UPV/EHU), Donostia-San Sebastián, Spain ,grid.452382.a0000 0004 1768 3100Donostia International Physics Center (DIPC), Donostia-San Sebastián, Spain ,grid.424810.b0000 0004 0467 2314Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Dimas G. de Oteyza
- Centro de Física de Materiales MPC (CSIC-UPV/EHU), Donostia-San Sebastián, Spain ,grid.452382.a0000 0004 1768 3100Donostia International Physics Center (DIPC), Donostia-San Sebastián, Spain ,grid.424810.b0000 0004 0467 2314Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Thomas Frederiksen
- grid.452382.a0000 0004 1768 3100Donostia International Physics Center (DIPC), Donostia-San Sebastián, Spain ,grid.424810.b0000 0004 0467 2314Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Diego Peña
- grid.11794.3a0000000109410645Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Jose Ignacio Pascual
- grid.424265.30000 0004 1761 1166CIC nanoGUNE-BRTA, Donostia-San Sebastián, Spain ,grid.424810.b0000 0004 0467 2314Ikerbasque, Basque Foundation for Science, Bilbao, Spain
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