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Sergentu DC, Le Guennic B, Maurice R. The resolution of the weak-exchange limit made rigorous, simple and general in binuclear complexes. Phys Chem Chem Phys 2024; 26:6844-6861. [PMID: 38328993 DOI: 10.1039/d3cp04943d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
The correct interpretation of magnetic properties in the weak-exchange regime has remained a challenging task for several decades. In this regime, the effective exchange interaction between local spins is quite weak, of the same order of magnitude or smaller than the various anisotropic terms, which generates a complex set of levels characterized by spin mixing. Although the model multispin Hamiltonian in the absence of local orbital momentum, , is considered good enough to map the experimental energies at zero field and in the strong-exchange limit, theoretical works pointed out limitations of this simple model. This work revives the use of ĤMS from a new theoretical perspective, detailing point-by-point a strategy to correctly map the computational energies and wave functions onto ĤMS, thus validating it regardless of the exchange limit. We will distinguish two cases, based on experimentally characterized dicobalt(II) complexes from the literature. If centrosymmetry imposes alignment of the various rank-2 tensors constitutive of ĤMS in the first case, the absence of any symmetry element prevents such alignment in the second case. In such a context, the strategy provided herein becomes a powerful tool to rationalize the experimental magnetic data, since it is capable of fully and rigorously extracting the multispin model without any assumption on the orientation of its constitutive tensors. Furthermore, the strategy allows to question the use of the spin Hamiltonian approach by explicitly controlling the projection norms on the model space, which is showcased in the second complex where local orbital momentum could have occurred (distorted octahedra). Finally, previous theoretical data related to a known dinickel(II) complex is reinterpreted, clarifying initial wanderings regarding the weak exchange limit.
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Affiliation(s)
- Dumitru-Claudiu Sergentu
- Univ Rennes, CNRS ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, 35000 Rennes, France.
- Laboratorul RA-03 (RECENT AIR), Universitatea Alexandru Ioan Cuza din Iaşi, 700506 Iaşi, Romania
- Facultatea de Chimie, Universitatea Alexandru Ioan Cuza din Iaşi, 700506 Iaşi, Romania
| | - Boris Le Guennic
- Univ Rennes, CNRS ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, 35000 Rennes, France.
| | - Rémi Maurice
- Univ Rennes, CNRS ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, 35000 Rennes, France.
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Chiesa A, Santini P, Garlatti E, Luis F, Carretta S. Molecular nanomagnets: a viable path toward quantum information processing? REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:034501. [PMID: 38314645 DOI: 10.1088/1361-6633/ad1f81] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 01/17/2024] [Indexed: 02/06/2024]
Abstract
Molecular nanomagnets (MNMs), molecules containing interacting spins, have been a playground for quantum mechanics. They are characterized by many accessible low-energy levels that can be exploited to store and process quantum information. This naturally opens the possibility of using them as qudits, thus enlarging the tools of quantum logic with respect to qubit-based architectures. These additional degrees of freedom recently prompted the proposal for encoding qubits with embedded quantum error correction (QEC) in single molecules. QEC is the holy grail of quantum computing and this qudit approach could circumvent the large overhead of physical qubits typical of standard multi-qubit codes. Another important strength of the molecular approach is the extremely high degree of control achieved in preparing complex supramolecular structures where individual qudits are linked preserving their individual properties and coherence. This is particularly relevant for building quantum simulators, controllable systems able to mimic the dynamics of other quantum objects. The use of MNMs for quantum information processing is a rapidly evolving field which still requires to be fully experimentally explored. The key issues to be settled are related to scaling up the number of qudits/qubits and their individual addressing. Several promising possibilities are being intensively explored, ranging from the use of single-molecule transistors or superconducting devices to optical readout techniques. Moreover, new tools from chemistry could be also at hand, like the chiral-induced spin selectivity. In this paper, we will review the present status of this interdisciplinary research field, discuss the open challenges and envisioned solution paths which could finally unleash the very large potential of molecular spins for quantum technologies.
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Affiliation(s)
- A Chiesa
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
- INFN-Sezione di Milano-Bicocca, Gruppo Collegato di Parma, 43124 Parma, Italy
- UdR Parma, INSTM, I-43124 Parma, Italy
| | - P Santini
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
- INFN-Sezione di Milano-Bicocca, Gruppo Collegato di Parma, 43124 Parma, Italy
- UdR Parma, INSTM, I-43124 Parma, Italy
| | - E Garlatti
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
- INFN-Sezione di Milano-Bicocca, Gruppo Collegato di Parma, 43124 Parma, Italy
- UdR Parma, INSTM, I-43124 Parma, Italy
| | - F Luis
- Instituto de Nanociencia y Materiales de Aragon (INMA), CSIC, Universidad de Zaragoza, Zaragoza, Spain
- Departamento de Fısica de la Materia Condensada, Universidad de Zaragoza, Zaragoza, Spain
| | - S Carretta
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
- INFN-Sezione di Milano-Bicocca, Gruppo Collegato di Parma, 43124 Parma, Italy
- UdR Parma, INSTM, I-43124 Parma, Italy
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3
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Yang K, Sun R, Zhao J, Deng C, Wang B, Gao S, Huang W. A Combined Synthetic, Magnetic, and Theoretical Study on Enhancing Ligand-Field Axiality for Dy(III) Single-Molecule Magnets Supported by Ferrocene Diamide Ligands. Inorg Chem 2023. [PMID: 37311100 DOI: 10.1021/acs.inorgchem.3c00896] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Molecular design is crucial for improving the performance of single-molecule magnets (SMMs). For dysprosium(III) SMMs, enhancing ligand-field axiality is a well-suited strategy to achieve high-performance SMMs. We synthesized a series of dysprosium(III) complexes, (NNTIPS)DyBr(THF)2 (1, NNTIPS = fc(NSiiPr3)2; fc = 1,1'-ferrocenediyl, THF = tetrahydrofuran), [(NNTIPS)Dy(THF)3][BPh4] (2), (NNTIPS)DyI(THF)2 (3), and [(NNTBS)Dy(THF)3][BPh4] (4, NNTBS = fc(NSitBuMe2)2), supported by ferrocene diamide ligands. X-ray crystallography shows that the rigid ferrocene backbone enforces a nearly axial ligand field with weakly coordinating equatorial ligands. Dysprosium(III) complexes 1-4 all exhibit slow magnetic relaxation under zero fields and possess high effective barriers (Ueff) around 1000 K, comparable to previously reported (NNTBS)DyI(THF)2 (5). We probed the influences of structural variations on SMM behaviors by theoretical calculations and found that the distribution of negative charges defined by rq, i.e., the ratio of the charges on the axial ligands to the charges on the equatorial ligands, plays a decisive role. Moreover, theoretical calculations on a series of model complexes 1'-5' without equatorial ligands unveil that the axial crystal-field parameters B20 are directly proportional to the N-Dy-N angles and support the hypothesis that enhancing the ligand-field axiality could improve SMM performance.
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Affiliation(s)
- Kexin Yang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Rong Sun
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Jingliang Zhao
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Chong Deng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Bingwu Wang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Song Gao
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
- Spin-X Institute, School of Chemistry and Chemical Engineering, State Key Laboratory of Luminescent Materials and Devices, Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, South China University of Technology, Guangzhou 510641, P. R. China
| | - Wenliang Huang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
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Long-lived electronic spin qubits in single-walled carbon nanotubes. Nat Commun 2023; 14:848. [PMID: 36792597 PMCID: PMC9932135 DOI: 10.1038/s41467-023-36031-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 01/12/2023] [Indexed: 02/17/2023] Open
Abstract
Electron spins in solid-state systems offer the promise of spin-based information processing devices. Single-walled carbon nanotubes (SWCNTs), an all-carbon one-dimensional material whose spin-free environment and weak spin-orbit coupling promise long spin coherence times, offer a diverse degree of freedom for extended range of functionality not available to bulk systems. A key requirement limiting spin qubit implementation in SWCNTs is disciplined confinement of isolated spins. Here, we report the creation of highly confined electron spins in SWCNTs via a bottom-up approach. The record long coherence time of 8.2 µs and spin-lattice relaxation time of 13 ms of these electronic spin qubits allow demonstration of quantum control operation manifested as Rabi oscillation. Investigation of the decoherence mechanism reveals an intrinsic coherence time of tens of milliseconds. These findings evident that combining molecular approaches with inorganic crystalline systems provides a powerful route for reproducible and scalable quantum materials suitable for qubit applications.
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Kotaru S, Kähler S, Alessio M, Krylov AI. Magnetic exchange interactions in binuclear and tetranuclear iron(III) complexes described by spin-flip DFT and Heisenberg effective Hamiltonians. J Comput Chem 2023; 44:367-380. [PMID: 35699152 PMCID: PMC10084445 DOI: 10.1002/jcc.26941] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 04/07/2022] [Accepted: 04/22/2022] [Indexed: 12/31/2022]
Abstract
Low-energy spectra of single-molecule magnets (SMMs) are often described by Heisenberg Hamiltonians. Within this formalism, exchange interactions between magnetic centers determine the ground-state multiplicity and energy separation between the ground and excited states. In this contribution, we extract exchange coupling constants (J) for a set of iron (III) binuclear and tetranuclear complexes from all-electron calculations using non-collinear spin-flip time-dependent density functional theory (NC-SF-TDDFT). For 12 binuclear complexes with J-values ranging from -6 to -132 cm-1 , our benchmark calculations using the short-range hybrid ωPBEh functional and 6-31G(d,p) basis set agree well with the experimentally derived values (mean absolute error of 4.7 cm-1 ). For the tetranuclear SMMs, the computed J constants are within 6 cm-1 from the experimentally derived values. We explore the range of applicability of the Heisenberg model by analyzing bonding patterns in these Fe(III) complexes using natural orbitals (NO), their occupations, and the number of effectively unpaired electrons. The results illustrate the efficiency of the spin-flip protocol for computing the exchange couplings and the utility of the NO analysis in assessing the validity of effective spin Hamiltonians.
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Affiliation(s)
- Saikiran Kotaru
- Department of ChemistryUniversity of Southern CaliforniaLos AngelesCalifornia
| | - Sven Kähler
- Department of ChemistryUniversity of Southern CaliforniaLos AngelesCalifornia
| | - Maristella Alessio
- Department of ChemistryUniversity of Southern CaliforniaLos AngelesCalifornia
| | - Anna I. Krylov
- Department of ChemistryUniversity of Southern CaliforniaLos AngelesCalifornia
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6
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Fang YH, Liu Z, Zhou S, Fu PX, Wang YX, Wang ZY, Wang ZM, Gao S, Jiang SD. Spin-Electric Coupling with Anisotropy-Induced Vanishment and Enhancement in Molecular Ferroelectrics. J Am Chem Soc 2022; 144:8605-8612. [PMID: 35512343 DOI: 10.1021/jacs.2c00484] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Manipulating quantum properties by electric fields using spin-electric coupling (SEC) effects promises spatial addressability. While several studies about inorganic materials showing the SEC functionality have been reported, the vastly tunable crystal structures of molecular ferroelectrics provide a range of rationally designable materials yet to be exploited. In this work, Mn2+-doped molecular ferroelectrics are chosen to experimentally demonstrate the feasibility of achieving the quantum coherent SEC effect in molecular ferroelectrics for the first time. The electric field pulse applied between Hahn-echo pulses in electron paramagnetic resonance (EPR) experiments causes controllable phase shifts via manipulating of the zero-field splitting (ZFS) of the Mn(II) ions. Detailed investigations of the aMn crystal showed unexpected SEC vanishment and enhancement at different crystal orientations, which were elucidated by studying the spin Hamiltonian and magnetic anisotropy. With the enhanced SEC efficiency being achieved (0.68 Hz m/V), this work discovers an emerging material library of molecular ferroelectrics to implement coherent quantum control with selective and tunable SEC effects toward highly scalable quantum gates.
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Affiliation(s)
- Yu-Hui Fang
- Beijing National Laboratory of Molecular Science, Beijing Key Laboratory of Magnetoelectric Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Zheng Liu
- Spin-X Institute, School of Chemistry and Chemical Engineering, State Key Laboratory of Luminescent Materials and Devices, Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, South China University of Technology, Guangzhou 510641, China
| | - Shen Zhou
- Spin-X Institute, School of Chemistry and Chemical Engineering, State Key Laboratory of Luminescent Materials and Devices, Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, South China University of Technology, Guangzhou 510641, China.,College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073, China
| | - Peng-Xiang Fu
- Beijing National Laboratory of Molecular Science, Beijing Key Laboratory of Magnetoelectric Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Ye-Xin Wang
- Spin-X Institute, School of Chemistry and Chemical Engineering, State Key Laboratory of Luminescent Materials and Devices, Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, South China University of Technology, Guangzhou 510641, China
| | - Zi-Yu Wang
- Beijing National Laboratory of Molecular Science, Beijing Key Laboratory of Magnetoelectric Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Zhe-Ming Wang
- Beijing National Laboratory of Molecular Science, Beijing Key Laboratory of Magnetoelectric Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Song Gao
- Beijing National Laboratory of Molecular Science, Beijing Key Laboratory of Magnetoelectric Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.,Spin-X Institute, School of Chemistry and Chemical Engineering, State Key Laboratory of Luminescent Materials and Devices, Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, South China University of Technology, Guangzhou 510641, China
| | - Shang-Da Jiang
- Spin-X Institute, School of Chemistry and Chemical Engineering, State Key Laboratory of Luminescent Materials and Devices, Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, South China University of Technology, Guangzhou 510641, China
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7
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Wu D, Zhou C, Bao JJ, Gagliardi L, Truhlar DG. Zero-Field Splitting Calculations by Multiconfiguration Pair-Density Functional Theory. J Chem Theory Comput 2022; 18:2199-2207. [PMID: 35319874 DOI: 10.1021/acs.jctc.1c01115] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Zero-field splitting (ZFS) is a fundamental molecular property that is especially relevant for single-molecule magnets (SMMs), electron paramagnetic resonance spectra, and quantum computing. Developing a method that can accurately predict ZFS parameters can be very powerful for designing new SMMs. One of the challenges is to include external correlation in an inherently multiconfigurational open-shell species for the accurate prediction of magnetic properties. Previously available methods depend on expensive multireference perturbation theory calculations to include external correlation. In this paper, we present spin-orbit-inclusive multiconfiguration and multistate pair-density functional theory (MC-PDFT) calculations of ZFSs; these calculations have a cost comparable to complete-active-space self-consistent field (CASSCF) theory, but they include correlation external to the active space. We found that combining a multistate formulation of MC-PDFT, namely, compressed-state multistate pair-density functional theory, with orbitals optimized by weighted-state-averaged CASSCF, yields reasonably accurate ZFS results.
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Affiliation(s)
- Dihua Wu
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Chen Zhou
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Jie J Bao
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Laura Gagliardi
- Department of Chemistry, Pritzker School of Molecular Engineering, The James Franck Institute, and Chicago Center for Theoretical Chemistry, The University of Chicago, Chicago, Illinois 60637, United States.,Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Donald G Truhlar
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
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8
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Cheng Y, Liu Q, Chen ZY, Zhang YZ. A cyanide-bridged Fe-Co pearl-chain-like single-chain magnet containing 4-coordinate cobalt(II) ions. Dalton Trans 2021; 50:17372-17377. [PMID: 34792060 DOI: 10.1039/d1dt02844h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Treatment of CoCl2·6H2O and tris(pyrazolyl-1-yl)borate tricyanoiron(III) anions at an elevated temperature (55 °C) afforded two less-common pearl-chain-like compounds, {[(TpR)Fe(CN)3CoCl2]2Co(DMF)4}·nDMF (1, TpR = Tp4-Me = hydridotris(4-methylpyrazol-1-yl)borate, n = 1 and 2, TpR = Tp*Me = hydridotris(3,4,5-trimethylpyrazol-1-yl)borate, n = 4.5), in which the 4-coordinate Co(II) ions and [(TpR)FeIII(CN)3]- units are alternately bridged by cyanide groups into squares, which are further linked with the 6-coordinate Co(II) ions into an infinite chain. Interestingly, the magnetic study revealed that 1 exhibits a typical single-chain magnet behaviour with an effective energy barrier of 28.0 K, while surprisingly no Glauber dynamics was observed for 2 despite their very similar structures. The variations of the local coordination environments of the cobalt ions and the cyanide linkages were evidenced, and they may account for the significant difference in their magnetic properties related to the global magnetic anisotropy and magnetic exchange of the chain.
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Affiliation(s)
- Yue Cheng
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, P. R. China.
| | - Qi Liu
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, P. R. China.
| | - Zi-Yi Chen
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, P. R. China.
| | - Yuan-Zhu Zhang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, P. R. China.
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9
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López-Moreno A, del Carmen Giménez-López M. Metallic-based magnetic switches under confinement. ADVANCES IN ORGANOMETALLIC CHEMISTRY 2021. [DOI: 10.1016/bs.adomc.2021.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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10
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Perfetti M, Caneschi A, Sukhikh TS, Vostrikova KE. Lanthanide Complexes with a Tripodal Nitroxyl Radical Showing Strong Magnetic Coupling. Inorg Chem 2020; 59:16591-16598. [PMID: 33119277 DOI: 10.1021/acs.inorgchem.0c02477] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of isomorphous mononuclear complexes of Ln(III) ions comprising one stable tripodal oxazolidine nitroxyl radical were obtained in acetonitrile media starting from nitrates. The compounds, [LnRad(NO3)3] (Ln = Gd, Tb, Dy, Tm, Y; Rad = 4,4-dimethyl-2,2-bis(pyridin-2-yl)-1,3-oxazolidine-3-oxyl), have a molecular structure. Their coordination polyhedron, LnO7N2, can be described as a tricapped trigonal prism with symmetry not far from D3h. The extracted value of 23 cm-1 for the antiferromagnetic coupling of Gd-Rad established from the DC magnetic and EPR data is a record strength for the complexes of 4f elements with nitroxyl radicals. The terbium derivative displays frequency-dependent out-of-phase signals in zero field, indicating single-molecule magnetic behavior. With an applied field of 0.1 T, an effective barrier of 57 cm-1 is found.
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Affiliation(s)
- Mauro Perfetti
- Department of Chemistry U. Schiff, University of Florence and INSTM Reseach Unit, Via della Lastruccia 3-13, Sesto Fiorentino, 50019 Firenze, Italy
| | - Andrea Caneschi
- Dipartimento di Ingegneria Industriale - DIEF, Università degli Studi di Firenze, INSTM Research Unit of Firenze, Via di Santa Marta n. 3, 50139 Firenze, Italy
| | - Taisiya S Sukhikh
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Kira E Vostrikova
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
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11
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Najafi K, Wysocki AL, Park K, Economou SE, Barnes E. Toward Long-Range Entanglement between Electrically Driven Single-Molecule Magnets. J Phys Chem Lett 2019; 10:7347-7355. [PMID: 31715105 DOI: 10.1021/acs.jpclett.9b03131] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Over the past two decades, several molecules have been explored as possible building blocks of a quantum computer, a device that would provide exponential speedups for a number of problems, including the simulation of large, strongly correlated chemical systems. Achieving strong interactions and entanglement between molecular qubits remains an outstanding challenge. Here, we show that the TbPc2 single-molecule magnet has the potential to overcome this obstacle because of its sensitivity to electric fields stemming from the hyperfine Stark effect. We show how this feature can be leveraged to achieve long-range entanglement between pairs of molecules using a superconducting resonator as a mediator. Our results suggest that the molecule-resonator interaction is near the edge of the strong-coupling regime and could potentially pass into it given a more detailed, quantitative understanding of the TbPc2 molecule.
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Affiliation(s)
- Khadijeh Najafi
- Department of Physics , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Aleksander L Wysocki
- Department of Physics , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Kyungwha Park
- Department of Physics , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Sophia E Economou
- Department of Physics , Virginia Tech , Blacksburg , Virginia 24061 , United States
| | - Edwin Barnes
- Department of Physics , Virginia Tech , Blacksburg , Virginia 24061 , United States
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12
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Jackson CE, Lin CY, Johnson SH, van Tol J, Zadrozny JM. Nuclear-spin-pattern control of electron-spin dynamics in a series of V(iv) complexes. Chem Sci 2019; 10:8447-8454. [PMID: 31803424 PMCID: PMC6839508 DOI: 10.1039/c9sc02899d] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 07/27/2019] [Indexed: 12/28/2022] Open
Abstract
Achieving control of phase memory relaxation times (T m) in metal ions is an important goal of molecular spintronics. Herein we provide the first evidence that nuclear-spin patterning in the ligand shell is an important handle to modulate T m in metal ions. We synthesized and studied a series of five V(iv) complexes with brominated catecholate ligands, [V(C6H4-n Br n O2)3]2- (n = 0, 1, 2, and 4), where the 79/81Br and 1H nuclear spins are arranged in different substitutional patterns. High-field, high-frequency (120 GHz) pulsed electron paramagnetic resonance spectroscopic analysis of this series reveals a pattern-dependent variation in T m for the V(iv) ion. Notably, we show that it is possible for two molecules to have starkly different (by 50%) T m values despite the same chemical composition. Nuclear magnetic resonance analyses of the protons on the ligand shell suggest that relative chemical shift (δ), controlled by the patterning of nuclear spins, is an important underlying design principle. Here, having multiple ligand-based protons with nearly identical chemical shift values in the ligand shell will, ultimately, engender a short T m for the bound metal ion.
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Affiliation(s)
- Cassidy E Jackson
- Department of Chemistry , Colorado State University , Fort Collins , CO 80523 , USA .
| | - Chun-Yi Lin
- Department of Chemistry , Colorado State University , Fort Collins , CO 80523 , USA .
| | - Spencer H Johnson
- Department of Chemistry , Colorado State University , Fort Collins , CO 80523 , USA .
| | - Johan van Tol
- National High Magnetic Field Laboratory , Tallahassee , FL 32310 , USA
| | - Joseph M Zadrozny
- Department of Chemistry , Colorado State University , Fort Collins , CO 80523 , USA .
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13
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Cebulka R, Del Barco E. Sub-Kelvin (100 mK) time resolved electron paramagnetic resonance spectroscopy for studies of quantum dynamics of low-dimensional spin systems at low frequencies and magnetic fields. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:085106. [PMID: 31472653 DOI: 10.1063/1.5097563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 07/22/2019] [Indexed: 06/10/2023]
Abstract
This article presents a time-resolved electron paramagnetic resonance spectrometry setup designed to work at frequencies below 20 GHz and temperatures down to 50 mK. The setup consists of an on-chip microstrip resonator (Q < 100) placed in a dilution cryostat located within a superconducting 3D vector magnet. A housemade spin echo circuitry controlled by a microwave network analyzer, a pulse pattern generator, and an oscilloscope connects to the microstrip through a series of copper, stainless steel, and superconducting semirigid coaxial lines which are thermally anchored to the different cooling stages of the fridge by means of power attenuators, circulators, and a cryogenic amplifier. Spin echo experiments were performed at a 0.5-T magnetic field on a spin 1 2 paramagnetic coal marker sample mounted on a 15 GHz microstrip resonator at temperatures ranging from 100 to 800 mK. The results show an increase in echo signal intensity as temperature is decreased until saturation as theoretically expected in reaching 99% spin polarization at 100 mK. Our technique allows tuning of the spin system in the pure-state regime and minimizing dipolar fluctuations, which are the main contribution to decoherence in solid-state samples of single-molecule magnets (SMMs) - molecular spin systems that are currently being tested for applications in quantum computation. The achievement of full spin polarization at 100 mK will allow for coherent control over the time evolution of spin systems without the need for large magnetic fields (commonly used to polarize the dipolar bath at higher temperatures) and high frequencies.
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Affiliation(s)
- Rebecca Cebulka
- Physics Department, University of Central Florida, Orlando, Florida 32816, USA
| | - Enrique Del Barco
- Physics Department, University of Central Florida, Orlando, Florida 32816, USA
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14
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Pokhilko P, Epifanovsky E, Krylov AI. General framework for calculating spin-orbit couplings using spinless one-particle density matrices: Theory and application to the equation-of-motion coupled-cluster wave functions. J Chem Phys 2019; 151:034106. [PMID: 31325926 DOI: 10.1063/1.5108762] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Standard implementations of nonrelativistic excited-state calculations compute only one component of spin multiplets (i.e., Ms = 0 triplets); however, matrix elements for all components are necessary for deriving spin-dependent experimental observables. Wigner-Eckart's theorem allows one to circumvent explicit calculations of all multiplet components. We generate all other spin-orbit matrix elements by applying Wigner-Eckart's theorem to a reduced one-particle transition density matrix computed for a single multiplet component. In addition to computational efficiency, this approach also resolves the phase issue arising within Born-Oppenheimer's separation of nuclear and electronic degrees of freedom. A general formalism and its application to the calculation of spin-orbit couplings using equation-of-motion coupled-cluster wave functions are presented. The two-electron contributions are included via the mean-field spin-orbit treatment. Intrinsic issues of constructing spin-orbit mean-field operators for open-shell references are discussed, and a resolution is proposed. The method is benchmarked by using several radicals and diradicals. The merits of the approach are illustrated by a calculation of the barrier for spin inversion in a high-spin tris(pyrrolylmethyl)amine Fe(II) complex.
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Affiliation(s)
- Pavel Pokhilko
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA
| | - Evgeny Epifanovsky
- Q-Chem, Inc., 6601 Owens Drive, Suite 105, Pleasanton, California 94588, USA
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA and Institut für Physikalische Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
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15
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Lenz S, Bamberger H, Hallmen PP, Thiebes Y, Otto S, Heinze K, van Slageren J. Chromium(iii)-based potential molecular quantum bits with long coherence times. Phys Chem Chem Phys 2019; 21:6976-6983. [PMID: 30869710 DOI: 10.1039/c9cp00745h] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular quantum bits based on copper(ii) or vanadium(iv) have been shown to possess long coherence times on multiple occasions. In contrast, studies in which non-spin-½ ions are employed are relatively scarce. High-spin ions provide additional states that can be used to encode further quantum bits. Furthermore, an optical rather than a microwave readout of molecular quantum bits is highly desirable, because in principle it could allow addressing at the single quantum bit level. The chromium(iii) complex [Cr(ddpd)2]3+ (ddpd = N,N'-dimethyl-N,N'-dipyridine-2-yl-pyridine-2,6-diamine) combines both the large spin (S = 3/2) and optical activity (strong, long lived luminescence). Here we demonstrate that the compound possesses coherence times of up to 8.4(1) μs, which are much longer (at least three times) than those for other chromium(iii)-based compounds. On the other hand, it is proved to be impossible to read out or influence the quantum state by optical means, underlining that further work is needed in this direction.
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Affiliation(s)
- Samuel Lenz
- Institute of Physical Chemistry and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany.
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16
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Cornia A, Mannini M, Sessoli R, Gatteschi D. Propeller-Shaped Fe4
and Fe3
M Molecular Nanomagnets: A Journey from Crystals to Addressable Single Molecules. Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201801266] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Andrea Cornia
- Department of Chemical and Geological Sciences and INSTM Research Unit; University of Modena and Reggio Emilia; 41125 Modena Italy
| | - Matteo Mannini
- Department of Chemistry “Ugo Schiff” and INSTM Research Unit; University of Florence; 50019 Sesto Fiorentino (FI) Italy
| | - Roberta Sessoli
- Department of Chemistry “Ugo Schiff” and INSTM Research Unit; University of Florence; 50019 Sesto Fiorentino (FI) Italy
- Research Area Firenze; Istituto di Chimica dei Composti Organometallici - ICCOM-CNR; 50019 Sesto Fiorentino (FI) Italy
| | - Dante Gatteschi
- Department of Chemistry “Ugo Schiff” and INSTM Research Unit; University of Florence; 50019 Sesto Fiorentino (FI) Italy
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17
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Orms N, Krylov AI. Singlet-triplet energy gaps and the degree of diradical character in binuclear copper molecular magnets characterized by spin-flip density functional theory. Phys Chem Chem Phys 2018; 20:13127-13144. [PMID: 29376159 DOI: 10.1039/c7cp07356a] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Molecular magnets, defined here as organic polyradicals, can be used as building blocks in the fabrication of novel and structurally diverse magnetic light-weight materials. We present a theoretical investigation of the lowest spin states of several binuclear copper diradicals. In contrast to previous studies, we consider not only the energetics of the low-lying states (which are related to the exchange-coupling parameter within the Heisenberg-Dirac-van-Vleck model), but also the character of the diradical states themselves. We use natural orbitals, their occupations, and the number of effectively unpaired electrons to quantify bonding patterns in these systems. We compare the performance of spin-flip time-dependent density functional theory (SF-TDDFT) using various functionals and effective core potentials against the wave function based approach, equation-of-motion spin-flip coupled-cluster method with single and double substitutions (EOM-SF-CCSD). We find that SF-TDDFT paired with the PBE50 and B5050LYP functionals performs comparably to EOM-SF-CCSD, with respect to both singlet-triplet gaps and states' characters. Visualization of frontier natural orbitals shows that the unpaired electrons are localized on copper centers, in some cases exhibiting slight through-bond interaction via copper d-orbitals and p-orbitals of neighboring ligand atoms. The analysis reveals considerable interactions between the formally unpaired electrons in the antiferromagnetic diradicaloids, meaning that they are poorly described by the Heisenberg-Dirac-van-Vleck model. Thus, for these systems the experimentally derived exchange-coupling parameters are not directly comparable with the singlet-triplet gaps. This explains systematic discrepancies between the computed singlet-triplet energy gaps and the exchange-coupling parameters extracted from experiment.
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Affiliation(s)
- Natalie Orms
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA.
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA.
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18
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Morita T, Damjanović M, Katoh K, Kitagawa Y, Yasuda N, Lan Y, Wernsdorfer W, Breedlove BK, Enders M, Yamashita M. Comparison of the Magnetic Anisotropy and Spin Relaxation Phenomenon of Dinuclear Terbium(III) Phthalocyaninato Single-Molecule Magnets Using the Geometric Spin Arrangement. J Am Chem Soc 2018; 140:2995-3007. [PMID: 29400960 DOI: 10.1021/jacs.7b12667] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Herein we report the synthesis and characterization of a dinuclear TbIII single-molecule magnet (SMM) with two [TbPc2]0 units connected via a fused-phthalocyaninato ligand. The stable and robust complex [(obPc)Tb(Fused-Pc)Tb(obPc)] (1) was characterized by using synchrotron radiation measurements and other spectroscopic techniques (ESI-MS, FT-IR, UV). The magnetic couplings between the TbIII ions and the two π radicals present in 1 were explored by means of density functional theory (DFT). Direct and alternating current magnetic susceptibility measurements were conducted on magnetically diluted and nondiluted samples of 1, indicating this compound to be an SMM with improved properties compared to those of the well-known [TbPc2]-/0/+ and the axially symmetric dinuclear TbIII phthalocyaninato triple-decker complex (Tb2(obPc)3). Assuming that the probability of quantum tunneling of the magnetization (QTM) occurring in one TbPc2 unit is PQTM, the probability of QTM simultaneously occurring in 1 is PQTM2, meaning that QTM is effectively suppressed. Furthermore, nondiluted samples of 1 underwent slow magnetic relaxation times (τ ≈ 1000 s at 0.1 K), and the blocking temperature (TB) was determined to be ca. 16 K with an energy barrier for spin reversal (Ueff) of 588 cm-1 (847 K) due to D4d geometry and weak inter- and intramolecular magnetic interactions as an exchange bias (Hbias), reducing QTM. Four hyperfine steps were observed by micro-SQUID measurement. Furthermore, solution NMR measurements (one-dimensional, two-dimensional, and dynamic) were done on 1, which led to the determination of the high rotation barrier (83 ± 10 kJ/mol) of the obPc ligand. A comparison with previously reported TbIII triple-decker compounds shows that ambient temperature NMR measurements can indicate improvements in the design of coordination environments for SMMs. A large Ueff causes strong uniaxial magnetic anisotropy in 1, leading to a χax value (1.39 × 10-30 m3) that is larger than that for Tb2(obPc)3 (0.86 × 10-30 m3). Controlling the coordination environment and spin arrangement is an effective technique for suppressing QTM in TbPc2-based SMMs.
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Affiliation(s)
- Takaumi Morita
- Department of Chemistry, Graduate School of Science, Tohoku University , 6-3, Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Marko Damjanović
- Institute of Inorganic Chemistry, Heidelberg University , Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.,Physikalisches Institut and Institute of Nanotechnology, Karlsruhe Institute of Technology , Wolfgang-Gaede-Strasse 1, 76131 Karlsruhe, Germany
| | - Keiichi Katoh
- Department of Chemistry, Graduate School of Science, Tohoku University , 6-3, Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Yasutaka Kitagawa
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University , 1-1 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Nobuhiro Yasuda
- Japan Synchrotron Radiation Research Institute (JASRI) , 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Yanhua Lan
- Physikalisches Institut and Institute of Nanotechnology, Karlsruhe Institute of Technology , Wolfgang-Gaede-Strasse 1, 76131 Karlsruhe, Germany
| | - Wolfgang Wernsdorfer
- Physikalisches Institut and Institute of Nanotechnology, Karlsruhe Institute of Technology , Wolfgang-Gaede-Strasse 1, 76131 Karlsruhe, Germany.,CNRS and Université Grenoble Alpes, Institut Néel , 38042 Grenoble, France
| | - Brian K Breedlove
- Department of Chemistry, Graduate School of Science, Tohoku University , 6-3, Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Markus Enders
- Institute of Inorganic Chemistry, Heidelberg University , Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
| | - Masahiro Yamashita
- Department of Chemistry, Graduate School of Science, Tohoku University , 6-3, Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan.,WPI Research Center, Advanced Institute for Materials Research, Tohoku University , 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.,School of Materials Science and Engineering, Nankai University , Tianjin 300350, China
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19
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Zadrozny JM, Graham MJ, Krzyaniak MD, Wasielewski MR, Freedman DE. Unexpected suppression of spin-lattice relaxation via high magnetic field in a high-spin iron(iii) complex. Chem Commun (Camb) 2018; 52:10175-8. [PMID: 27463410 DOI: 10.1039/c6cc05094h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A counterintuitive three-order of magnitude slowing of the spin-lattice relaxation rate is observed in a high spin qubit at high magnetic field via multifrequency pulsed electron paramagnetic resonance measurements.
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Affiliation(s)
- Joseph M Zadrozny
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA.
| | - Michael J Graham
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA.
| | - Matthew D Krzyaniak
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA. and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, IL 60208, USA
| | - Michael R Wasielewski
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA. and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, IL 60208, USA
| | - Danna E Freedman
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA.
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20
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Liu Z, Dong BW, Meng HB, Xu MX, Wang TS, Wang BW, Wang CR, Jiang SD, Gao S. Qubit crossover in the endohedral fullerene Sc 3C 2@C 80. Chem Sci 2018; 9:457-462. [PMID: 30310560 PMCID: PMC6113862 DOI: 10.1039/c7sc03749j] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Accepted: 11/02/2017] [Indexed: 01/03/2023] Open
Abstract
The core-shell structure of endohedral fullerenes results in good protection of the encapsulated spin carriers from the environment. In this research, the quantum coherence behavior of the endohedral fullerene Sc3C2@C80 in CS2 solution is characterized from 5 K to room temperature. Below the critical temperature of around 140 K, the inner group is hindered, and the EPR spectrum consists of a single broad line. The spin carriers display a maximum phase memory time of 17.2(7) μs at 10 K. In the high temperature region, the inner group is mobile, and the EPR spectrum consists of 22 homogeneously broadened lines due to isotropic hyperfine coupling. The maximum phase memory time for each transition is around 139(1) ns at 200 K which allows arbitrary superposition state manipulations to be performed. This research demonstrates that Sc3C2@C80 displays temperature-crossover behaviour due to weak interaction between the Sc3C2 core and the C80 shell.
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Affiliation(s)
- Zheng Liu
- National Laboratory for Molecular Sciences , State Key Laboratory of Rare Earth Materials Chemistry and Applications , College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China . ;
| | - Bo-Wei Dong
- National Laboratory for Molecular Sciences , State Key Laboratory of Rare Earth Materials Chemistry and Applications , College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China . ;
| | - Hai-Bing Meng
- Key Laboratory of Molecular Nanostructure and Nanotechnology , Beijing National Laboratory for Molecular Sciences , Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , P. R. China .
| | - Mei-Xing Xu
- National Laboratory for Molecular Sciences , State Key Laboratory of Rare Earth Materials Chemistry and Applications , College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China . ;
| | - Tai-Shan Wang
- Key Laboratory of Molecular Nanostructure and Nanotechnology , Beijing National Laboratory for Molecular Sciences , Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , P. R. China .
| | - Bing-Wu Wang
- National Laboratory for Molecular Sciences , State Key Laboratory of Rare Earth Materials Chemistry and Applications , College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China . ;
| | - Chun-Ru Wang
- Key Laboratory of Molecular Nanostructure and Nanotechnology , Beijing National Laboratory for Molecular Sciences , Institute of Chemistry , Chinese Academy of Sciences , Beijing 100190 , P. R. China .
| | - Shang-Da Jiang
- National Laboratory for Molecular Sciences , State Key Laboratory of Rare Earth Materials Chemistry and Applications , College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China . ;
| | - Song Gao
- National Laboratory for Molecular Sciences , State Key Laboratory of Rare Earth Materials Chemistry and Applications , College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China . ;
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21
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Hu Z, Dong BW, Liu Z, Liu JJ, Su J, Yu C, Xiong J, Shi DE, Wang Y, Wang BW, Ardavan A, Shi Z, Jiang SD, Gao S. Endohedral Metallofullerene as Molecular High Spin Qubit: Diverse Rabi Cycles in Gd2@C79N. J Am Chem Soc 2018; 140:1123-1130. [DOI: 10.1021/jacs.7b12170] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ziqi Hu
- National
Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth
Materials Chemistry and Applications, Beijing Key Laboratory for Magnetoelectric
Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Bo-Wei Dong
- National
Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth
Materials Chemistry and Applications, Beijing Key Laboratory for Magnetoelectric
Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Zheng Liu
- National
Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth
Materials Chemistry and Applications, Beijing Key Laboratory for Magnetoelectric
Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Jun-Jie Liu
- CAESR,
The Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, U.K
| | - Jie Su
- National
Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth
Materials Chemistry and Applications, Beijing Key Laboratory for Magnetoelectric
Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Changcheng Yu
- National
Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth
Materials Chemistry and Applications, Beijing Key Laboratory for Magnetoelectric
Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Jin Xiong
- National
Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth
Materials Chemistry and Applications, Beijing Key Laboratory for Magnetoelectric
Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Di-Er Shi
- National
Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth
Materials Chemistry and Applications, Beijing Key Laboratory for Magnetoelectric
Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Yuanyuan Wang
- National
Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth
Materials Chemistry and Applications, Beijing Key Laboratory for Magnetoelectric
Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Bing-Wu Wang
- National
Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth
Materials Chemistry and Applications, Beijing Key Laboratory for Magnetoelectric
Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Arzhang Ardavan
- CAESR,
The Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, U.K
| | - Zujin Shi
- National
Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth
Materials Chemistry and Applications, Beijing Key Laboratory for Magnetoelectric
Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Shang-Da Jiang
- National
Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth
Materials Chemistry and Applications, Beijing Key Laboratory for Magnetoelectric
Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Song Gao
- National
Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth
Materials Chemistry and Applications, Beijing Key Laboratory for Magnetoelectric
Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
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22
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23
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Field-Induced Slow Magnetic Relaxation of Mono- and Dinuclear Dysprosium(III) Complexes Coordinated by a Chloranilate with Different Resonance Forms. INORGANICS 2017. [DOI: 10.3390/inorganics6010007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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24
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Katoh K, Aizawa Y, Morita T, Breedlove BK, Yamashita M. Elucidation of Dual Magnetic Relaxation Processes in Dinuclear Dysprosium(III) Phthalocyaninato Triple-Decker Single-Molecule Magnets Depending on the Octacoordination Geometry. Chemistry 2017; 23:15377-15386. [PMID: 28782141 DOI: 10.1002/chem.201703014] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Indexed: 11/10/2022]
Abstract
When applying single-molecule magnets (SMMs) to spintronic devices, control of the quantum tunneling of the magnetization (QTM) as well as a spin-lattice interactions are important. Attempts have been made to use not only coordination geometry but also magnetic interactions between SMMs as an exchange bias. In this manuscript, dinuclear dysprosium(III) (DyIII ) SMMs with the same octacoordination geometry undergo dual magnetic relaxation processes at low temperature. In the dinuclear DyIII phthalocyaninato (Pc2- ) triple-decker type complex [(Pc)Dy(ooPc)Dy(Pc)] (1) (ooPc2- =2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyaninato) with a square-antiprismatic (SAP) geometry, the ground state is divided by the Zeeman effect, and level intersection occurs when a magnetic field is applied. Due to the ground state properties of 1, since the Zeeman diagram where the levels intersect in an Hdc of 2500 Oe, two kinds of QTM and direct processes occur. However, dinuclear DyIII -Pc systems with C4 geometry, which have a twist angle (ϕ) of less than 45° do not undergo dual magnetic relaxation processes. From magnetic field and temperature dependences, the dual magnetic relaxation processes were clarified.
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Affiliation(s)
- Keiichi Katoh
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Yu Aizawa
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Takaumi Morita
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Brian K Breedlove
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Masahiro Yamashita
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aza-Aoba, Aoba-ku, Sendai, Miyagi, 980-8578, Japan.,WPI Research Center, Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan.,China School of Materials Science and Engineering, Nankai University, Tianjin, 300350, P. R. China
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25
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McAdams SG, Ariciu AM, Kostopoulos AK, Walsh JP, Tuna F. Molecular single-ion magnets based on lanthanides and actinides: Design considerations and new advances in the context of quantum technologies. Coord Chem Rev 2017. [DOI: 10.1016/j.ccr.2017.03.015] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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26
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Wu DQ, Shao D, Wei XQ, Shen FX, Shi L, Kempe D, Zhang YZ, Dunbar KR, Wang XY. Reversible On–Off Switching of a Single-Molecule Magnet via a Crystal-to-Crystal Chemical Transformation. J Am Chem Soc 2017; 139:11714-11717. [DOI: 10.1021/jacs.7b07008] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Dong-Qing Wu
- State
Key Laboratory of Coordination Chemistry, Collaborative Innovation
Center of Advanced Microstructures, School of Chemistry and Chemical
Engineering, Nanjing University, Nanjing 210023, China
| | - Dong Shao
- State
Key Laboratory of Coordination Chemistry, Collaborative Innovation
Center of Advanced Microstructures, School of Chemistry and Chemical
Engineering, Nanjing University, Nanjing 210023, China
| | - Xiao-Qin Wei
- State
Key Laboratory of Coordination Chemistry, Collaborative Innovation
Center of Advanced Microstructures, School of Chemistry and Chemical
Engineering, Nanjing University, Nanjing 210023, China
| | - Fu-Xing Shen
- State
Key Laboratory of Coordination Chemistry, Collaborative Innovation
Center of Advanced Microstructures, School of Chemistry and Chemical
Engineering, Nanjing University, Nanjing 210023, China
| | - Le Shi
- State
Key Laboratory of Coordination Chemistry, Collaborative Innovation
Center of Advanced Microstructures, School of Chemistry and Chemical
Engineering, Nanjing University, Nanjing 210023, China
| | - David Kempe
- Department of Chemistry, Texas A&M University, College Station, Texas 77840, United States
| | - Yuan-Zhu Zhang
- Department
of Chemistry, South University of Science and Technology of China, Shenzhen 518055, China
| | - Kim R. Dunbar
- Department of Chemistry, Texas A&M University, College Station, Texas 77840, United States
| | - Xin-Yi Wang
- State
Key Laboratory of Coordination Chemistry, Collaborative Innovation
Center of Advanced Microstructures, School of Chemistry and Chemical
Engineering, Nanjing University, Nanjing 210023, China
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27
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Uber JS, Estrader M, Garcia J, Lloyd‐Williams P, Sadurní A, Dengler D, van Slageren J, Chilton NF, Roubeau O, Teat SJ, Ribas‐Ariño J, Aromí G. Molecules Designed to Contain Two Weakly Coupled Spins with a Photoswitchable Spacer. Chemistry 2017. [DOI: 10.1002/chem.201702171] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Jorge Salinas Uber
- Departament de Química Inorgànica i Orgànica Universitat de Barcelona Diagonal 645 08028 Barcelona Spain
| | - Marta Estrader
- Departament de Química Inorgànica i Orgànica Universitat de Barcelona Diagonal 645 08028 Barcelona Spain
| | - Jordi Garcia
- Departament de Química Inorgànica i Orgànica Universitat de Barcelona Diagonal 645 08028 Barcelona Spain
| | - Paul Lloyd‐Williams
- Departament de Química Inorgànica i Orgànica Universitat de Barcelona Diagonal 645 08028 Barcelona Spain
| | - Anna Sadurní
- Departament de Química Inorgànica i Orgànica Universitat de Barcelona Diagonal 645 08028 Barcelona Spain
| | - Dominik Dengler
- Institut für Physikalische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany) and Center for Integrated Quantum Science and Technology (IQST), Stuttgart/Ulm (Germany
| | - Joris van Slageren
- Institut für Physikalische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany) and Center for Integrated Quantum Science and Technology (IQST), Stuttgart/Ulm (Germany
| | - Nicholas F. Chilton
- School of Chemistry The University of Manchester Oxford Road Manchester M13 9PL United Kingdom
| | - Olivier Roubeau
- Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC Universidad de Zaragoza Plaza San Francisco s/n 50009 Zaragoza Spain
| | - Simon J. Teat
- Advanced Light Source Berkeley Laboratory 1 Cyclotron Road Berkeley California 94720 USA
| | - Jordi Ribas‐Ariño
- Departament de Ciència de Materials i Química Física and IQTCUB Universitat de Barcelona Diagonal 645 08028 Barcelona Spain
| | - Guillem Aromí
- Departament de Química Inorgànica i Orgànica Universitat de Barcelona Diagonal 645 08028 Barcelona Spain
- Institute of Nanoscience and Nanotechnology (IN2UB) Universitat de Barcelona Spain
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Zaripov R, Vavilova E, Khairuzhdinov I, Salikhov K, Voronkova V, Abdulmalic MA, Meva FE, Weheabby S, Rüffer T, Büchner B, Kataev V. Tuning the spin coherence time of Cu(II)-(bis)oxamato and Cu(II)-(bis)oxamidato complexes by advanced ESR pulse protocols. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:943-955. [PMID: 28546889 PMCID: PMC5433190 DOI: 10.3762/bjnano.8.96] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 03/29/2017] [Indexed: 06/07/2023]
Abstract
We have investigated with the pulsed ESR technique at X- and Q-band frequencies the coherence and relaxation of Cu spins S = 1/2 in single crystals of diamagnetically diluted mononuclear [n-Bu4N]2[Cu(opba)] (1%) in the host lattice of [n-Bu4N]2[Ni(opba)] (99%, opba = o-phenylenebis(oxamato)) and of diamagnetically diluted mononuclear [n-Bu4N]2[Cu(opbon-Pr2)] (1%) in the host lattice of [n-Bu4N]2[Ni(opbon-Pr2)] (99%, opbon-Pr2 = o-phenylenebis(N(propyl)oxamidato)). For that we have measured the electron spin dephasing time Tm at different temperatures with the two-pulse primary echo and with the special Carr-Purcell-Meiboom-Gill (CPMG) multiple microwave pulse sequence. Application of the CPMG protocol has led to a substantial increase of the spin coherence lifetime in both complexes as compared to the primary echo results. It shows the efficiency of the suppression of the electron spin decoherence channel in the studied complexes arising due to spectral diffusion induced by a random modulation of the hyperfine interaction with the nuclear spins. We argue that this method can be used as a test for the relevance of the spectral diffusion for the electron spin decoherence. Our results have revealed a prominent role of the opba4- and opbon-Pr24- ligands for the dephasing of the Cu spins. The presence of additional 14N nuclei and protons in [Cu(opbon-Pr2)]2- as compared to [Cu(opba)]2- yields significantly shorter Tm times. Such a detrimental effect of the opbon-Pr24- ligands has to be considered when discussing a potential application of the Cu(II)-(bis)oxamato and Cu(II)-(bis)oxamidato complexes as building blocks of more complex molecular structures in prototype spintronic devices. Furthermore, in our work we propose an improved CPMG pulse protocol that enables elimination of unwanted echoes that inevitably appear in the case of inhomogeneously broadened ESR spectra due to the selective excitation of electron spins.
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Affiliation(s)
- Ruslan Zaripov
- Kazan E. K. Zavoisky Physical -Technical Institute, Russian Academy of Sciences, 420029 Kazan, Russia
| | - Evgeniya Vavilova
- Kazan E. K. Zavoisky Physical -Technical Institute, Russian Academy of Sciences, 420029 Kazan, Russia
| | - Iskander Khairuzhdinov
- Kazan E. K. Zavoisky Physical -Technical Institute, Russian Academy of Sciences, 420029 Kazan, Russia
| | - Kev Salikhov
- Kazan E. K. Zavoisky Physical -Technical Institute, Russian Academy of Sciences, 420029 Kazan, Russia
| | - Violeta Voronkova
- Kazan E. K. Zavoisky Physical -Technical Institute, Russian Academy of Sciences, 420029 Kazan, Russia
| | - Mohammad A Abdulmalic
- Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Chemie, Straße der Nationen 62, D-09111 Chemnitz, Germany
| | - Francois E Meva
- Department of Pharmaceutical Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, BP 2701, Cameroon
| | - Saddam Weheabby
- Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Chemie, Straße der Nationen 62, D-09111 Chemnitz, Germany
| | - Tobias Rüffer
- Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Chemie, Straße der Nationen 62, D-09111 Chemnitz, Germany
| | - Bernd Büchner
- Leibniz Institute for Solid State and Materials Research IFW Dresden, D-01171 Dresden, Germany
- Institut für Festkörperphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - Vladislav Kataev
- Leibniz Institute for Solid State and Materials Research IFW Dresden, D-01171 Dresden, Germany
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29
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Yu CJ, Graham MJ, Zadrozny JM, Niklas J, Krzyaniak MD, Wasielewski MR, Poluektov OG, Freedman DE. Long Coherence Times in Nuclear Spin-Free Vanadyl Qubits. J Am Chem Soc 2016; 138:14678-14685. [PMID: 27797487 DOI: 10.1021/jacs.6b08467] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Quantum information processing (QIP) offers the potential to create new frontiers in fields ranging from quantum biology to cryptography. Two key figures of merit for electronic spin qubits, the smallest units of QIP, are the coherence time (T2), the lifetime of the qubit, and the spin-lattice relaxation time (T1), the thermally defined upper limit of T2. To achieve QIP, processable qubits with long coherence times are required. Recent studies on (Ph4P-d20)2[V(C8S8)3], a vanadium-based qubit, demonstrate that millisecond T2 times are achievable in transition metal complexes with nuclear spin-free environments. Applying these principles to vanadyl complexes offers a route to combine the previously established surface compatibility of the flatter vanadyl structures with a long T2. Toward those ends, we investigated a series of four qubits, (Ph4P)2[VO(C8S8)2] (1), (Ph4P)2[VO(β-C3S5)2] (2), (Ph4P)2[VO(α-C3S5)2] (3), and (Ph4P)2[VO(C3S4O)2] (4), by pulsed electron paramagnetic resonance (EPR) spectroscopy and compared the performance of these species with our recently reported set of vanadium tris(dithiolene) complexes. Crucially we demonstrate that solutions of 1-4 in SO2, a uniquely polar nuclear spin-free solvent, reveal T2 values of up to 152(6) μs, comparable to the best molecular qubit candidates. Upon transitioning to vanadyl species from the tris(dithiolene) analogues, we observe a remarkable order of magnitude increase in T1, attributed to stronger solute-solvent interactions with the polar vanadium-oxo moiety. Simultaneously, we detect a small decrease in T2 for the vanadyl analogues relative to the tris(dithiolene) complexes. We attribute this decrease to the absence of one nuclear spin-free ligand, which served to shield the vanadium centers against solvent nuclear spins. Our results highlight new design principles for long T1 and T2 times by demonstrating the efficacy of ligand-based tuning of solute-solvent interactions.
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Affiliation(s)
- Chung-Jui Yu
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Michael J Graham
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Joseph M Zadrozny
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Jens Niklas
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Matthew D Krzyaniak
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.,Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Michael R Wasielewski
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.,Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University , Evanston, Illinois 60208-3113, United States
| | - Oleg G Poluektov
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Danna E Freedman
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
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30
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Xiong J, Ding HY, Meng YS, Gao C, Zhang XJ, Meng ZS, Zhang YQ, Shi W, Wang BW, Gao S. Hydroxide-bridged five-coordinate Dy III single-molecule magnet exhibiting the record thermal relaxation barrier of magnetization among lanthanide-only dimers. Chem Sci 2016; 8:1288-1294. [PMID: 28451271 PMCID: PMC5359878 DOI: 10.1039/c6sc03621j] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Accepted: 10/01/2016] [Indexed: 12/24/2022] Open
Abstract
A hydroxide-bridged five-coordinate dysprosium(iii) dimer with short Dy–O bonds was synthesized.
A hydroxide-bridged centrosymmetric DyIII dimer with each DyIII being five-coordinated has been synthesized using bulky hindered phenolate ligands. Magnetic studies revealed that this compound exhibits a slow magnetic relaxation of a single-ion origin together with a step-like magnetic hysteresis of the magnetic coupled cluster. The thermal relaxation barrier of magnetization is 721 K in the absence of a static magnetic field, while the intramolecular magnetic interaction is very large among reported 4f-only dimers. CASSCF calculations with a larger active space were performed to understand the electronic structure of the compound. The thermal relaxation regime and the quantum tunneling regime are well separated, representing a good model to study the relaxation mechanism of SMMs with intramolecular Dy–Dy magnetic interactions.
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Affiliation(s)
- Jin Xiong
- Beijing National Laboratory of Molecular Science , College of Chemistry and Molecular Engineering , State Key Laboratory of Rare Earth Materials Chemistry and Applications , Peking University , Beijing , 100871 , P. R. China . ; ; http://www.chem.pku.edu.cn/mmm/
| | - Hai-Yan Ding
- Jiangsu Key Laboratory for NSLSCS , School of Physical Science and Technology , Nanjing Normal University , Nanjing 210023 , P. R. China
| | - Yin-Shan Meng
- Beijing National Laboratory of Molecular Science , College of Chemistry and Molecular Engineering , State Key Laboratory of Rare Earth Materials Chemistry and Applications , Peking University , Beijing , 100871 , P. R. China . ; ; http://www.chem.pku.edu.cn/mmm/
| | - Chen Gao
- Beijing National Laboratory of Molecular Science , College of Chemistry and Molecular Engineering , State Key Laboratory of Rare Earth Materials Chemistry and Applications , Peking University , Beijing , 100871 , P. R. China . ; ; http://www.chem.pku.edu.cn/mmm/
| | - Xue-Jing Zhang
- Department of Chemistry , Key Laboratory of Advanced Energy Materials Chemistry (MOE) , State Key Laboratory of Elemento-Organic Chemistry , Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Nankai University , Tianjin 300071 , China
| | - Zhao-Sha Meng
- Beijing National Laboratory of Molecular Science , College of Chemistry and Molecular Engineering , State Key Laboratory of Rare Earth Materials Chemistry and Applications , Peking University , Beijing , 100871 , P. R. China . ; ; http://www.chem.pku.edu.cn/mmm/
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS , School of Physical Science and Technology , Nanjing Normal University , Nanjing 210023 , P. R. China
| | - Wei Shi
- Department of Chemistry , Key Laboratory of Advanced Energy Materials Chemistry (MOE) , State Key Laboratory of Elemento-Organic Chemistry , Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Nankai University , Tianjin 300071 , China
| | - Bing-Wu Wang
- Beijing National Laboratory of Molecular Science , College of Chemistry and Molecular Engineering , State Key Laboratory of Rare Earth Materials Chemistry and Applications , Peking University , Beijing , 100871 , P. R. China . ; ; http://www.chem.pku.edu.cn/mmm/
| | - Song Gao
- Beijing National Laboratory of Molecular Science , College of Chemistry and Molecular Engineering , State Key Laboratory of Rare Earth Materials Chemistry and Applications , Peking University , Beijing , 100871 , P. R. China . ; ; http://www.chem.pku.edu.cn/mmm/
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31
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Chen Y, Ashkezari MD, Collett CA, Allão Cassaro RA, Troiani F, Lahti PM, Friedman JR. Observation of Tunneling-Assisted Highly Forbidden Single-Photon Transitions in a Ni_{4} Single-Molecule Magnet. PHYSICAL REVIEW LETTERS 2016; 117:187202. [PMID: 27835005 DOI: 10.1103/physrevlett.117.187202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Indexed: 06/06/2023]
Abstract
Forbidden transitions between energy levels typically involve violation of selection rules imposed by symmetry and/or conservation laws. A nanomagnet tunneling between up and down states violates angular momentum conservation because of broken rotational symmetry. Here we report observations of highly forbidden transitions between spin states in a Ni_{4} single-molecule magnet in which a single photon can induce the spin to change by several times ℏ, nearly reversing the direction of the spin. These observations are understood as tunneling-assisted transitions that lift the standard Δm=±1 selection rule for single-photon transitions. These transitions are observed at low applied fields, where tunneling is dominated by the molecule's intrinsic anisotropy and the field acts as a perturbation. Such transitions can be exploited to create macroscopic superposition states that are not typically accessible through single-photon Δm=±1 transitions.
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Affiliation(s)
- Yiming Chen
- Department of Physics and Astronomy, Amherst College, Amherst, Massachusetts 01002-5000, USA
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Mohammad D Ashkezari
- Department of Physics and Astronomy, Amherst College, Amherst, Massachusetts 01002-5000, USA
| | - Charles A Collett
- Department of Physics and Astronomy, Amherst College, Amherst, Massachusetts 01002-5000, USA
| | | | | | - Paul M Lahti
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Jonathan R Friedman
- Department of Physics and Astronomy, Amherst College, Amherst, Massachusetts 01002-5000, USA
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33
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Vaidya S, Tewary S, Singh SK, Langley SK, Murray KS, Lan Y, Wernsdorfer W, Rajaraman G, Shanmugam M. What Controls the Sign and Magnitude of Magnetic Anisotropy in Tetrahedral Cobalt(II) Single-Ion Magnets? Inorg Chem 2016; 55:9564-9578. [DOI: 10.1021/acs.inorgchem.6b01073] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shefali Vaidya
- Department
of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra India
| | - Subrata Tewary
- Department
of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra India
| | - Saurabh Kumar Singh
- Department
of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra India
| | - Stuart K. Langley
- School
of Science and the Environment, Chemistry Division, Manchester Metropolitan University, Manchester M15 6HB, U.K
| | - Keith S. Murray
- School
of Chemistry, Monash University, Clayton 3800, Victoria, Australia
| | - Yanhua Lan
- Institut
Néel, CNRS and Université Grenoble Alpes, BP 166,
25 Avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - Wolfgang Wernsdorfer
- Institut
Néel, CNRS and Université Grenoble Alpes, BP 166,
25 Avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - Gopalan Rajaraman
- Department
of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra India
| | - Maheswaran Shanmugam
- Department
of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra India
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34
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Jenkins MD, Zueco D, Roubeau O, Aromí G, Majer J, Luis F. A scalable architecture for quantum computation with molecular nanomagnets. Dalton Trans 2016; 45:16682-16693. [PMID: 27711709 DOI: 10.1039/c6dt02664h] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A proposal for a magnetic quantum processor that consists of individual molecular spins coupled to superconducting coplanar resonators and transmission lines is carefully examined. We derive a simple magnetic quantum electrodynamics Hamiltonian to describe the underlying physics. It is shown that these hybrid devices can perform arbitrary operations on each spin qubit and induce tunable interactions between any pair of them. The combination of these two operations ensures that the processor can perform universal quantum computations. The feasibility of this proposal is critically discussed using the results of realistic calculations, based on parameters of existing devices and molecular qubits. These results show that the proposal is feasible, provided that molecules with sufficiently long coherence times can be developed and accurately integrated into specific areas of the device. This architecture has an enormous potential for scaling up quantum computation thanks to the microscopic nature of the individual constituents, the molecules, and the possibility of using their internal spin degrees of freedom.
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Affiliation(s)
- M D Jenkins
- Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC and Universidad de Zaragoza, Zaragoza, Spain.
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35
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On the Use of Classical and Quantum Fisher Information in Molecular Magnetism. MAGNETOCHEMISTRY 2016. [DOI: 10.3390/magnetochemistry2030033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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36
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Espín J, Zarzuela R, Statuto N, Juanhuix J, Maspoch D, Imaz I, Chudnovsky E, Tejada J. Narrowing the Zero-Field Tunneling Resonance by Decreasing the Crystal Symmetry of Mn12 Acetate. J Am Chem Soc 2016; 138:9065-8. [DOI: 10.1021/jacs.6b05380] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jordi Espín
- Catalan
Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Ricardo Zarzuela
- Departament
de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - Nahuel Statuto
- Departament
de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - Jordi Juanhuix
- Alba Synchrotron Light Facility, 08290 Cerdanyola del Vallés, Barcelona, Spain
| | - Daniel Maspoch
- Catalan
Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- ICREA, Pg Lluı́s Companys 23, 08100 Barcelona, Spain
| | - Inhar Imaz
- Catalan
Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Eugene Chudnovsky
- Physics
Department, Lehman College, The City University of New York, 250 Bedford
Park Boulevard West, Bronx, New York 10468-1589, United States
| | - Javier Tejada
- Departament
de Física Fonamental, Facultat de Física, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
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37
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Pedersen KS, Ariciu AM, McAdams S, Weihe H, Bendix J, Tuna F, Piligkos S. Toward Molecular 4f Single-Ion Magnet Qubits. J Am Chem Soc 2016; 138:5801-4. [DOI: 10.1021/jacs.6b02702] [Citation(s) in RCA: 167] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Kasper S. Pedersen
- CNRS, CRPP, UPR 8641, F-33600 Pessac, France
- CNRS, ICMCB, UPR 9014, F-33600 Pessac, France
| | - Ana-Maria Ariciu
- School
of Chemistry and Photon Science Institute, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Simon McAdams
- School
of Chemistry and Photon Science Institute, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Høgni Weihe
- Department
of Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Jesper Bendix
- Department
of Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Floriana Tuna
- School
of Chemistry and Photon Science Institute, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Stergios Piligkos
- Department
of Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark
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38
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Fataftah MS, Zadrozny JM, Coste SC, Graham MJ, Rogers DM, Freedman DE. Employing Forbidden Transitions as Qubits in a Nuclear Spin-Free Chromium Complex. J Am Chem Soc 2016; 138:1344-8. [DOI: 10.1021/jacs.5b11802] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Majed S. Fataftah
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Joseph M. Zadrozny
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Scott C. Coste
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Michael J. Graham
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Dylan M. Rogers
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Danna E. Freedman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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39
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Zadrozny J, Niklas J, Poluektov OG, Freedman DE. Millisecond Coherence Time in a Tunable Molecular Electronic Spin Qubit. ACS CENTRAL SCIENCE 2015; 1:488-92. [PMID: 27163013 PMCID: PMC4827467 DOI: 10.1021/acscentsci.5b00338] [Citation(s) in RCA: 209] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Indexed: 05/02/2023]
Abstract
Quantum information processing (QIP) could revolutionize areas ranging from chemical modeling to cryptography. One key figure of merit for the smallest unit for QIP, the qubit, is the coherence time (T 2), which establishes the lifetime for the qubit. Transition metal complexes offer tremendous potential as tunable qubits, yet their development is hampered by the absence of synthetic design principles to achieve a long T 2. We harnessed molecular design to create a series of qubits, (Ph4P)2[V(C8S8)3] (1), (Ph4P)2[V(β-C3S5)3] (2), (Ph4P)2[V(α-C3S5)3] (3), and (Ph4P)2[V(C3S4O)3] (4), with T 2s of 1-4 μs at 80 K in protiated and deuterated environments. Crucially, through chemical tuning of nuclear spin content in the vanadium(IV) environment we realized a T 2 of ∼1 ms for the species (d 20-Ph4P)2[V(C8S8)3] (1') in CS2, a value that surpasses the coordination complex record by an order of magnitude. This value even eclipses some prominent solid-state qubits. Electrochemical and continuous wave electron paramagnetic resonance (EPR) data reveal variation in the electronic influence of the ligands on the metal ion across 1-4. However, pulsed measurements indicate that the most important influence on decoherence is nuclear spins in the protiated and deuterated solvents utilized herein. Our results illuminate a path forward in synthetic design principles, which should unite CS2 solubility with nuclear spin free ligand fields to develop a new generation of molecular qubits.
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Affiliation(s)
- Joseph
M. Zadrozny
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Jens Niklas
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Argonne, Illinois 60439, United States
| | - Oleg G. Poluektov
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Argonne, Illinois 60439, United States
| | - Danna E. Freedman
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- E-mail:
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40
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Tesi L, Lucaccini E, Cimatti I, Perfetti M, Mannini M, Atzori M, Morra E, Chiesa M, Caneschi A, Sorace L, Sessoli R. Quantum coherence in a processable vanadyl complex: new tools for the search of molecular spin qubits. Chem Sci 2015; 7:2074-2083. [PMID: 29899933 PMCID: PMC5968563 DOI: 10.1039/c5sc04295j] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/11/2015] [Indexed: 12/11/2022] Open
Abstract
A multitechnique investigation of an evaporable vanadyl spin system with long-lived quantum coherence that self-assembles on gold.
Electronic spins in different environments are currently investigated as potential qubits, i.e. the logic units of quantum computers. These have to retain memory of their quantum state for a sufficiently long time (phase memory time, Tm) allowing quantum operations to be performed. For molecular based spin qubits, strategies to increase phase coherence by removing nuclear spins are rather well developed, but it is now crucial to address the problem of the rapid increase of the spin–lattice relaxation rate, T1–1, with increasing temperature that hampers their use at room-temperature. Herein, thanks to the combination of pulsed EPR spectroscopy and AC susceptometry we evidence that an evaporable vanadyl complex of formula VO(dpm)2, where dpm– is the anion of dipivaloylmethane, presents a combination of very promising features for potential application as molecular spin-qubit. The spin–lattice relaxation time, T1, studied in detail through AC susceptometry, decreases slowly with increasing temperature and, more surprisingly, it is not accelerated by the application of an external field up to several Teslas. State-of-the art phase memory times for molecular spin systems in protiated environment are detected by pulsed EPR also in moderate dilution, with values of 2.7 μs at 5 K and 2.1 μs at 80 K. Low temperature scanning tunnel microscopy and X-ray photoelectron spectroscopy in situ investigations reveal that intact molecules sublimated in ultra-high vacuum spontaneously form an ordered monolayer on Au(111), opening the perspective of electric access to the quantum memory of ensembles of spin qubits that can be scaled down to the single molecule.
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Affiliation(s)
- Lorenzo Tesi
- Department of Chemistry "Ugo Schiff" , University of Florence & INSTM RU of Florence , Via della Lastruccia 3-13 , 50019 Sesto Fiorentino , Italy
| | - Eva Lucaccini
- Department of Chemistry "Ugo Schiff" , University of Florence & INSTM RU of Florence , Via della Lastruccia 3-13 , 50019 Sesto Fiorentino , Italy
| | - Irene Cimatti
- Department of Chemistry "Ugo Schiff" , University of Florence & INSTM RU of Florence , Via della Lastruccia 3-13 , 50019 Sesto Fiorentino , Italy
| | - Mauro Perfetti
- Department of Chemistry "Ugo Schiff" , University of Florence & INSTM RU of Florence , Via della Lastruccia 3-13 , 50019 Sesto Fiorentino , Italy
| | - Matteo Mannini
- Department of Chemistry "Ugo Schiff" , University of Florence & INSTM RU of Florence , Via della Lastruccia 3-13 , 50019 Sesto Fiorentino , Italy
| | - Matteo Atzori
- Department of Chemistry "Ugo Schiff" , University of Florence & INSTM RU of Florence , Via della Lastruccia 3-13 , 50019 Sesto Fiorentino , Italy
| | - Elena Morra
- Department of Chemistry , University of Turin & NIS Centre , via P. Giuria 7 , 10125 , Torino , Italy . ;
| | - Mario Chiesa
- Department of Chemistry , University of Turin & NIS Centre , via P. Giuria 7 , 10125 , Torino , Italy . ;
| | - Andrea Caneschi
- Department of Chemistry "Ugo Schiff" , University of Florence & INSTM RU of Florence , Via della Lastruccia 3-13 , 50019 Sesto Fiorentino , Italy
| | - Lorenzo Sorace
- Department of Chemistry "Ugo Schiff" , University of Florence & INSTM RU of Florence , Via della Lastruccia 3-13 , 50019 Sesto Fiorentino , Italy
| | - Roberta Sessoli
- Department of Chemistry "Ugo Schiff" , University of Florence & INSTM RU of Florence , Via della Lastruccia 3-13 , 50019 Sesto Fiorentino , Italy
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41
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Chien YL, Chang MW, Tsai YC, Lee GH, Sheu WS, Yang EC. New salen-type dysprosium(III) double-decker and triple-decker complexes. Polyhedron 2015. [DOI: 10.1016/j.poly.2015.07.048] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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42
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McInnes EJL, Timco GA, Whitehead GFS, Winpenny REP. Heterometallic Rings: Their Physics and use as Supramolecular Building Blocks. Angew Chem Int Ed Engl 2015; 54:14244-69. [PMID: 26459810 DOI: 10.1002/anie.201502730] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Indexed: 11/10/2022]
Abstract
An enormous family of heterometallic rings has been made. The first were Cr7 M rings where M = Ni(II), Zn(II), Mn(II), and rings have been made with as many as fourteen metal centers in the cyclic structure. They are bridged externally by carboxylates, and internally by fluorides or a penta-deprotonated polyol. The size of the rings is controlled through templates which have included a range of ammonium or imidazolium ions, alkali metals and coordination compounds. The rings can be functionalized to act as ligands, and incorporated into hybrid organic-inorganic rotaxanes and into molecules containing up to 200 metal centers. Physical studies reported include: magnetic measurements, inelastic neutron scattering (including single crystal measurements), electron paramagnetic resonance spectroscopy (including measurements of phase memory times), NMR spectroscopy (both solution and solid state), and polarized neutron diffraction. The rings are hence ideal for understanding magnetism in elegant exchange-coupled systems.
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Affiliation(s)
- Eric J L McInnes
- School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL (UK)
| | - Grigore A Timco
- School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL (UK)
| | - George F S Whitehead
- School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL (UK)
| | - Richard E P Winpenny
- School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL (UK).
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43
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McInnes EJL, Timco GA, Whitehead GFS, Winpenny REP. Heterometallische Ringe: physikalische Eigenschaften und Verwendung als supramolekulare Bausteine. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201502730] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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44
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Magazzù L, Valenti D, Spagnolo B, Grifoni M. Dissipative dynamics in a quantum bistable system: crossover from weak to strong damping. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:032123. [PMID: 26465442 DOI: 10.1103/physreve.92.032123] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Indexed: 06/05/2023]
Abstract
The dissipative dynamics of a quantum bistable system coupled to a Ohmic heat bath is investigated beyond the spin-boson approximation. Within the path-integral approach to quantum dissipation, we propose an approximation scheme which exploits the separation of time scales between intra- and interwell (tunneling) dynamics. The resulting generalized master equation for the populations in a space localized basis enables us to investigate a wide range of temperatures and system-environment coupling strengths. A phase diagram in the coupling-temperature space is provided to give a comprehensive account of the different dynamical regimes.
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Affiliation(s)
- Luca Magazzù
- Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, I-90128 Palermo, Italy
- Radiophysics Department, Lobachevsky State University of Nizhni Novgorod, Russia
| | - Davide Valenti
- Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, I-90128 Palermo, Italy
| | - Bernardo Spagnolo
- Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, I-90128 Palermo, Italy
- Radiophysics Department, Lobachevsky State University of Nizhni Novgorod, Russia
- Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Italy
| | - Milena Grifoni
- Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany
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45
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Dreiser J. Molecular lanthanide single-ion magnets: from bulk to submonolayers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:183203. [PMID: 25893740 DOI: 10.1088/0953-8984/27/18/183203] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Single-ion magnets (SIMs) are mononuclear molecular complexes exhibiting slow relaxation of magnetization. They are currently attracting a lot of interest because of potential applications in spintronics and quantum information processing. However, exploiting SIMs in, e.g. molecule-inorganic hybrid devices requires a fundamental understanding of the effects of molecule-substrate interactions on the SIM magnetic properties. In this review the properties of lanthanide SIMs in the bulk crystalline phase and deposited on surfaces in the (sub)monolayer regime are discussed. As a starting point trivalent lanthanide ions in a ligand field will be described, and the challenges in characterizing the ligand field are illustrated with a focus on several spectroscopic techniques which are able to give direct information on the ligand-field split energy levels. Moreover, the dominant mechanisms of magnetization relaxation in the bulk phase are discussed followed by an overview of SIMs relevant for surface deposition. Further, a short introduction will be given on x-ray absorption spectroscopy, x-ray magnetic circular dichroism and scanning tunneling microscopy. Finally, the recent experiments on surface-deposited SIMs will be reviewed, along with a discussion of future perspectives.
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Affiliation(s)
- J Dreiser
- Ecole Polytechnique Fédérale de Lausanne, ICMP, Station 3, CH-1015 Lausanne, Switzerland. Paul Scherrer Institut, Swiss Light Source, CH-5232 Villigen PSI, Switzerland
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46
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Schimpf AM, Ochsenbein ST, Gamelin DR. Surface Contributions to Mn(2+) Spin Dynamics in Colloidal Doped Quantum Dots. J Phys Chem Lett 2015; 6:457-463. [PMID: 26261963 DOI: 10.1021/jz5026678] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Colloidal impurity-doped quantum dots (QDs) are attractive model systems for testing the fundamental spin properties of semiconductor nanostructures relevant to future spin-based information processing technologies. Although static spin properties of this class of materials have been studied extensively in recent years, their spin dynamics remain largely unexplored. Here we use pulsed electron paramagnetic resonance (pEPR) spectroscopy to probe the spin relaxation dynamics of colloidal Mn(2+)-doped ZnO, ZnSe, and CdSe quantum dots in the limit of one Mn(2+) per QD. pEPR spectroscopy is particularly powerful for identifying the specific nuclei that accelerate electron spin relaxation in these QDs. We show that the spin-relaxation dynamics of these colloidal QDs are strongly influenced by dipolar coupling with proton nuclear spins outside the QDs and especially those directly at the QD surfaces. Using this information, we demonstrate that spin-relaxation times can be elongated significantly via ligand (or surface) deuteration or shell growth, providing two tools for chemical adjustment of spin dynamics in these nanomaterials. These findings advance our understanding of the spin properties of solution-grown semiconductor nanostructures relevant to spin-based information technologies.
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Affiliation(s)
- Alina M Schimpf
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Stefan T Ochsenbein
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Daniel R Gamelin
- Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
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Chiesa A, Whitehead GFS, Carretta S, Carthy L, Timco GA, Teat SJ, Amoretti G, Pavarini E, Winpenny REP, Santini P. Molecular nanomagnets with switchable coupling for quantum simulation. Sci Rep 2014; 4:7423. [PMID: 25502419 PMCID: PMC4262827 DOI: 10.1038/srep07423] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 11/17/2014] [Indexed: 11/09/2022] Open
Abstract
Molecular nanomagnets are attractive candidate qubits because of their wide inter- and intra-molecular tunability. Uniform magnetic pulses could be exploited to implement one- and two-qubit gates in presence of a properly engineered pattern of interactions, but the synthesis of suitable and potentially scalable supramolecular complexes has proven a very hard task. Indeed, no quantum algorithms have ever been implemented, not even a proof-of-principle two-qubit gate. Here we show that the magnetic couplings in two supramolecular {Cr7Ni}-Ni-{Cr7Ni} assemblies can be chemically engineered to fit the above requisites for conditional gates with no need of local control. Microscopic parameters are determined by a recently developed many-body ab-initio approach and used to simulate quantum gates. We find that these systems are optimal for proof-of-principle two-qubit experiments and can be exploited as building blocks of scalable architectures for quantum simulation.
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Affiliation(s)
- Alessandro Chiesa
- Dipartimento di Fisica e Scienze della Terra, Università di Parma, Parco Area delle Scienze 7/a, 43124 Parma, Italy
- Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - George F. S. Whitehead
- School of Chemistry and Photon Science Institute, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Stefano Carretta
- Dipartimento di Fisica e Scienze della Terra, Università di Parma, Parco Area delle Scienze 7/a, 43124 Parma, Italy
| | - Laura Carthy
- School of Chemistry and Photon Science Institute, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Grigore A. Timco
- School of Chemistry and Photon Science Institute, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Simon J. Teat
- Advanced Light Source, Lawrence Berkeley Laboratory, MS2-400 Berkeley, California 94720, USA
| | - Giuseppe Amoretti
- Dipartimento di Fisica e Scienze della Terra, Università di Parma, Parco Area delle Scienze 7/a, 43124 Parma, Italy
| | - Eva Pavarini
- Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich, Germany
- JARA High-Performance Computing
| | - Richard E. P. Winpenny
- School of Chemistry and Photon Science Institute, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Paolo Santini
- Dipartimento di Fisica e Scienze della Terra, Università di Parma, Parco Area delle Scienze 7/a, 43124 Parma, Italy
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Zadrozny JM, Niklas J, Poluektov OG, Freedman DE. Multiple quantum coherences from hyperfine transitions in a vanadium(IV) complex. J Am Chem Soc 2014; 136:15841-4. [PMID: 25340518 DOI: 10.1021/ja507846k] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report a vanadium complex in a nuclear-spin free ligand field that displays two key properties for an ideal candidate qubit system: long coherence times that persist at high temperature, T2 = 1.2 μs at 80 K, and the observation of quantum coherences from multiple transitions. The electron paramagnetic resonance (EPR) spectrum of the complex [V(C8S8)3](2-) displays multiple transitions arising from a manifold of states produced by the hyperfine coupling of the S = ½ electron spin and I = 7/2 nuclear spin. Transient nutation experiments reveal Rabi oscillations for multiple transitions. These observations suggest that each pair of hyperfine levels hosted within [V(C8S8)3](2-) are candidate qubits. The realization of multiple quantum coherences within a transition metal complex illustrates an emerging method of developing scalability and addressability in electron spin qubits. This study presents a rare molecular demonstration of multiple Rabi oscillations originating from separate transitions. These results extend observations of multiple quantum coherences from prior reports in solid-state compounds to the new realm of highly modifiable coordination compounds.
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Affiliation(s)
- Joseph M Zadrozny
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
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49
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Room temperature quantum coherence in a potential molecular qubit. Nat Commun 2014; 5:5304. [DOI: 10.1038/ncomms6304] [Citation(s) in RCA: 208] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 09/18/2014] [Indexed: 12/24/2022] Open
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50
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Fataftah MS, Zadrozny JM, Rogers DM, Freedman DE. A Mononuclear Transition Metal Single-Molecule Magnet in a Nuclear Spin-Free Ligand Environment. Inorg Chem 2014; 53:10716-21. [DOI: 10.1021/ic501906z] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Majed S. Fataftah
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Joseph M. Zadrozny
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Dylan M. Rogers
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Danna E. Freedman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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