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Kopciuszyński M, Stȩpniak-Dybala A, Zdyb R, Krawiec M. Emergent Dirac Fermions in Epitaxial Planar Silicene Heterostructure. NANO LETTERS 2024; 24:2175-2180. [PMID: 38181506 PMCID: PMC10885205 DOI: 10.1021/acs.nanolett.3c04046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2024]
Abstract
Silicene, a single layer of Si atoms, shares many remarkable electronic properties with graphene. So far, silicene has been synthesized in its epitaxial form on a few surfaces of solids. Thus, the problem of silicene-substrate interaction appears, which usually depresses the original electronic behavior but may trigger properties superior to those of bare components. We report the direct observation of robust Dirac-dispersed bands in epitaxial silicene grown on Au(111) films deposited on Si(111). By performing in-depth angle-resolved photoemission spectroscopy measurements, we reveal three pairs of one-dimensional bands with linear dispersion running in three different directions of an otherwise two-dimensional system. By combining these results with first-principles calculations, we explore the nature of these bands and point to strong interaction between subsystems forming a complex Si-Au heterostructure. These findings emphasize the essential role of interfacial coupling and open a unique materials platform for exploring exotic quantum phenomena and applications in future-generation nanoelectronics.
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Affiliation(s)
- Marek Kopciuszyński
- Institute of Physics, M. Curie-Sklodowska University, Pl. M. Curie-Skłodowskiej 1, 20-031 Lublin, Poland
| | - Agnieszka Stȩpniak-Dybala
- Institute of Physics, M. Curie-Sklodowska University, Pl. M. Curie-Skłodowskiej 1, 20-031 Lublin, Poland
| | - Ryszard Zdyb
- Institute of Physics, M. Curie-Sklodowska University, Pl. M. Curie-Skłodowskiej 1, 20-031 Lublin, Poland
| | - Mariusz Krawiec
- Institute of Physics, M. Curie-Sklodowska University, Pl. M. Curie-Skłodowskiej 1, 20-031 Lublin, Poland
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2
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Barboza AM, da Silva-Santos JA, Aliaga LCR, Bastos IN, Faria DF. Silicene growth mechanisms on Au(111) and Au(110) substrates. NANOTECHNOLOGY 2024; 35:165602. [PMID: 38176066 DOI: 10.1088/1361-6528/ad1aff] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Accepted: 01/04/2024] [Indexed: 01/06/2024]
Abstract
Despite the remarkable theoretical applications of silicene, its synthesis remains a complex task, with epitaxial growth being one of the main routes involving depositing evaporated Si atoms onto a suitable substrate. Additionally, the requirement for a substrate to maintain the silicene stability poses several difficulties in accurately determining the growth mechanisms and the resulting structures, leading to conflicting results in the literature. In this study, large-scale molecular dynamics simulations are performed to uncover the growth mechanisms and characteristics of epitaxially grown silicene sheets on Au(111) and Au(110) substrates, considering different temperatures and Si deposition rates. The growth process has been found to initiate with the nucleation of several independent islands homogeneously distributed on the substrate surface, which gradually merge to form a complete silicene sheet. The results consistently demonstrate the presence of a buckled silicene structure, although this characteristic is notably reduced when using an Au(111) substrate. Furthermore, the analysis also focuses on the quality and growth mode of the silicene sheets, considering the influence of temperature and deposition rate. The findings reveal a prevalence of the Frank-van der Merwe growth mode, along with diverse forms of defects throughout the sheets.
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Affiliation(s)
- Alexandre M Barboza
- Rio de Janeiro State University, Polytechnic Institute, 28625-570 Nova Friburgo, Rio de Janeiro, Brazil
| | - José A da Silva-Santos
- Rio de Janeiro State University, Polytechnic Institute, 28625-570 Nova Friburgo, Rio de Janeiro, Brazil
| | - Luis C R Aliaga
- Rio de Janeiro State University, Polytechnic Institute, 28625-570 Nova Friburgo, Rio de Janeiro, Brazil
| | - Ivan N Bastos
- Rio de Janeiro State University, Polytechnic Institute, 28625-570 Nova Friburgo, Rio de Janeiro, Brazil
| | - Daiara F Faria
- Rio de Janeiro State University, Polytechnic Institute, 28625-570 Nova Friburgo, Rio de Janeiro, Brazil
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3
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Masson L, Prévot G. Epitaxial growth and structural properties of silicene and other 2D allotropes of Si. NANOSCALE ADVANCES 2023; 5:1574-1599. [PMID: 36926561 PMCID: PMC10012843 DOI: 10.1039/d2na00808d] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
Since the breakthrough of graphene, considerable efforts have been made to search for two-dimensional (2D) materials composed of other group 14 elements, in particular silicon and germanium, due to their valence electronic configuration similar to that of carbon and their widespread use in the semiconductor industry. Silicene, the silicon counterpart of graphene, has been particularly studied, both theoretically and experimentally. Theoretical studies were the first to predict a low-buckled honeycomb structure for free-standing silicene possessing most of the outstanding electronic properties of graphene. From an experimental point of view, as no layered structure analogous to graphite exists for silicon, the synthesis of silicene requires the development of alternative methods to exfoliation. Epitaxial growth of silicon on various substrates has been widely exploited in attempts to form 2D Si honeycomb structures. In this article, we provide a comprehensive state-of-the-art review focusing on the different epitaxial systems reported in the literature, some of which having generated controversy and long debates. In the search for the synthesis of 2D Si honeycomb structures, other 2D allotropes of Si have been discovered and will also be presented in this review. Finally, with a view to applications, we discuss the reactivity and air-stability of silicene as well as the strategy devised to decouple epitaxial silicene from the underlying surface and its transfer to a target substrate.
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Affiliation(s)
| | - Geoffroy Prévot
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP F-75005 Paris France
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4
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Pisarra M, Gomez CV, Sindona A. Massive and massless plasmons in germanene nanosheets. Sci Rep 2022; 12:18624. [PMID: 36329251 PMCID: PMC9633710 DOI: 10.1038/s41598-022-23058-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 10/25/2022] [Indexed: 11/06/2022] Open
Abstract
Atomically thin crystals may exhibit peculiar dispersive electronic states equivalent to free charged particles of ultralight to ultraheavy masses. A rare coexistence of linear and parabolic dispersions yields correlated charge density modes exploitable for nanometric light confinement. Here, we use a time-dependent density-functional approach, under several levels of increasing accuracy, from the random-phase approximation to the Bethe-Salpeter equation formalism, to assess the role of different synthesized germanene samples as platforms for these plasmon excitations. In particular, we establish that both freestanding and some supported germenene monolayers can sustain infrared massless modes, resolved into an out-of-phase (optical) and an in-phase (acoustic) component. We further indicate precise experimental geometries that naturally host infrared massive modes, involving two different families of parabolic charge carriers. We thus show that the interplay of the massless and massive plasmons can be finetuned by applied extrinsic conditions or geometry deformations, which constitutes the core mechanism of germanene-based optoelectronic and plasmonic applications.
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Affiliation(s)
- Michele Pisarra
- Gruppo Collegato di Cosenza, Sezione dei Laboratori Nazionali di Frascati (LNF), Istituto Nazionale di Fisica Nucleare (INFN), Cubo 31C, 87036, Rende, CS, Italy
| | - Cristian Vacacela Gomez
- Facultad de Ciencias, Escuela Superior Politécnica de Chimborazo (ESPOCH), Riobamba, 060155, Ecuador
| | - Antonello Sindona
- Gruppo Collegato di Cosenza, Sezione dei Laboratori Nazionali di Frascati (LNF), Istituto Nazionale di Fisica Nucleare (INFN), Cubo 31C, 87036, Rende, CS, Italy. .,Dipartimento di Fisica, Università della Calabria, Via P. Bucci, Cubo 30C, 87036, Rende, CS, Italy.
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5
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Nazzari D, Genser J, Ritter V, Bethge O, Bertagnolli E, Grasser T, Weber WM, Lugstein A. Epitaxial Growth of Crystalline CaF 2 on Silicene. ACS APPLIED MATERIALS & INTERFACES 2022; 14:32675-32682. [PMID: 35793167 PMCID: PMC9305960 DOI: 10.1021/acsami.2c06293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Silicene is one of the most promising two-dimensional (2D) materials for the realization of next-generation electronic devices, owing to its high carrier mobility and band gap tunability. To fully control its electronic properties, an external electric field needs to be applied perpendicularly to the 2D lattice, thus requiring the deposition of an insulating layer that directly interfaces silicene, without perturbing its bidimensional nature. A promising material candidate is CaF2, which is known to form a quasi van der Waals interface with 2D materials as well as to maintain its insulating properties even at ultrathin scales. Here we investigate the epitaxial growth of thin CaF2 layers on different silicene phases by means of molecular beam epitaxy. Through electron diffraction images, we clearly show that CaF2 can be grown epitaxially on silicene even at low temperatures, with its domains fully aligned to the lattice of the underlying 2D structure. Moreover, in situ X-ray photoelectron spectroscopy data evidence that, upon CaF2 deposition, no changes in the chemical state of the silicon atoms can be detected, proving that no Si-Ca or Si-F bonds are formed. This clearly shows that the 2D layer is pristinely preserved underneath the insulating layer. Polarized Raman experiments show that silicene undergoes a structural change upon interaction with CaF2; however, it retains its two-dimensional character without transitioning to a sp3-hybridized silicon. For the first time, we have shown that CaF2 and silicene can be successfully interfaced, paving the way for the integration of silicon-based 2D materials in functional devices.
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Affiliation(s)
- Daniele Nazzari
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, 1040 Vienna, Austria
| | - Jakob Genser
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, 1040 Vienna, Austria
| | - Viktoria Ritter
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, 1040 Vienna, Austria
| | - Ole Bethge
- Infineon
Technologies Austria AG, Siemensstraße 2, 9500 Villach, Austria
| | - Emmerich Bertagnolli
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, 1040 Vienna, Austria
| | - Tibor Grasser
- Institute
for Microelectronics, Technische Universität
Wien, Gußhausstraße
27-29, 1040 Vienna, Austria
| | - Walter M. Weber
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, 1040 Vienna, Austria
| | - Alois Lugstein
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, 1040 Vienna, Austria
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6
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Krivenkov M, Marchenko D, Sajedi M, Fedorov A, Clark OJ, Sánchez-Barriga J, Rienks EDL, Rader O, Varykhalov A. On the problem of Dirac cones in fullerenes on gold. NANOSCALE 2022; 14:9124-9133. [PMID: 35723255 DOI: 10.1039/d1nr07981f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Artificial graphene based on molecular networks enables the creation of novel 2D materials with unique electronic and topological properties. Landau quantization has been demonstrated by CO molecules arranged on the two-dimensional electron gas on Cu(111) and the observation of electron quantization may succeed based on the created gauge fields. Recently, it was reported that instead of individual manipulation of CO molecules, simple deposition of nonpolar C60 molecules on Cu(111) and Au(111) produces artificial graphene as evidenced by Dirac cones in photoemission spectroscopy. Here, we show that C60-induced Dirac cones on Au(111) have a different origin. We argue that those are related to umklapp diffraction of surface electronic bands of Au on the molecular grid of C60 in the final state of photoemission. We test this alternative explanation by precisely probing the dimensionality of the observed conical features in the photoemission spectra, by varying both the incident photon energy and the degree of charge doping via alkali adatoms. Using density functional theory calculations and spin-resolved photoemission we reveal the origin of the replicating Au(111) bands and resolve them as deep leaky surface resonances derived from the bulk Au sp-band residing at the boundary of its surface projection. We also discuss the manifold nature of these resonances which gives rise to an onion-like Fermi surface of Au(111).
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Affiliation(s)
- M Krivenkov
- Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
| | - D Marchenko
- Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
| | - M Sajedi
- Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
| | - A Fedorov
- Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
- IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
- Joint Laboratory 'Functional Quantum Materials' at BESSY II, 12489, Berlin, Germany
| | - O J Clark
- Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
| | - J Sánchez-Barriga
- Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
| | - E D L Rienks
- Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
| | - O Rader
- Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
| | - A Varykhalov
- Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany.
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7
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Sun S, You JY, Duan S, Gou J, Luo YZ, Lin W, Lian X, Jin T, Liu J, Huang Y, Wang Y, Wee ATS, Feng YP, Shen L, Zhang JL, Chen J, Chen W. Epitaxial Growth of Ultraflat Bismuthene with Large Topological Band Inversion Enabled by Substrate-Orbital-Filtering Effect. ACS NANO 2022; 16:1436-1443. [PMID: 34918901 DOI: 10.1021/acsnano.1c09592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Quantum spin Hall (QSH) systems hold promises of low-power-consuming spintronic devices, yet their practical applications are extremely impeded by the small energy gaps. Fabricating QSH materials with large gaps, especially under the guidance of design principles, is essential for both scientific research and practical applications. Here, we demonstrate that large on-site atomic spin-orbit coupling can be directly exploited via the intriguing substrate-orbital-filtering effect to generate large-gap QSH systems and experimentally realized on the epitaxially synthesized ultraflat bismuthene on Ag(111). Theoretical calculations reveal that the underlying substrate selectively filters Bi pz orbitals away from the Fermi level, leading pxy orbitals with nonzero magnetic quantum numbers, resulting in large topological gap of ∼1 eV at the K point. The corresponding topological edge states are identified through scanning tunneling spectroscopy combined with density functional theory calculations. Our findings provide general strategies to design large-gap QSH systems and further explore their topology-related physics.
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Affiliation(s)
| | | | | | | | | | - Weinan Lin
- Department of Physics, Xiamen University, Xiamen 361005, China
| | | | - Tengyu Jin
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou 350207, China
| | | | - Yuli Huang
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou 350207, China
| | - Yihe Wang
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou 350207, China
| | | | | | | | - Jia Lin Zhang
- School of Physics, Southeast University, Nanjing 211189, China
| | | | - Wei Chen
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou 350207, China
- National University of Singapore (Suzhou) Research Institute, Suzhou 215123, China
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8
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Li Q, Liu X, Aklile EB, Li S, Hersam MC. Self-Assembled Borophene/Graphene Nanoribbon Mixed-Dimensional Heterostructures. NANO LETTERS 2021; 21:4029-4035. [PMID: 33928782 DOI: 10.1021/acs.nanolett.1c00909] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Atomically thin metal-semiconductor heterojunctions are highly desirable for nanoelectronic applications. However, coherent lateral stitching of distinct two-dimensional (2D) materials has traditionally required interfacial lattice matching and compatible growth conditions, which remains challenging for most systems. On the other hand, these constraints are relaxed in 2D/1D mixed-dimensional lateral heterostructures due to the increased structural degree of freedom. Here, we report the self-assembly of mixed-dimensional lateral heterostructures consisting of 2D metallic borophene and 1D semiconducting armchair-oriented graphene nanoribbons (aGNRs). With the sequential ultrahigh vacuum deposition of boron and 4,4″-dibromo-p-terphenyl as precursors on Ag(111) substrates, an on-surface polymerization process is systematically studied and refined including the transition from monomers to organometallic intermediates and finally demetallization that results in borophene/aGNR lateral heterostructures. High-resolution scanning tunneling microscopy and spectroscopy resolve the structurally and electronically abrupt interfaces in borophene/aGNR heterojunctions, thus providing insight that will inform ongoing efforts in pursuit of atomically precise nanoelectronics.
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Affiliation(s)
- Qiucheng Li
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Soochow Institute for Energy and Materials InnovationS (SIEMIS), Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies, Soochow University, Suzhou 215006, P. R. China
| | - Xiaolong Liu
- Applied Physics Graduate Program, Northwestern University, Evanston, Illinois 60208, United States
| | - Eden B Aklile
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Shaowei Li
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Applied Physics Graduate Program, Northwestern University, Evanston, Illinois 60208, United States
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois 60208, United States
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9
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Takahashi M. Flat Zigzag Silicene Nanoribbon with Be Bridge. ACS OMEGA 2021; 6:12099-12104. [PMID: 34056363 PMCID: PMC8154158 DOI: 10.1021/acsomega.1c00794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
The emergence of flat one- and two-dimensional materials, such as graphene and its nanoribbons, has promoted the rapid advance of the current nanotechnology. Silicene, a silicon analogue of graphene, has the great advantage of its compatibility with the present industrial processes based on silicon nanotechnology. The most significant issue for silicene is instability in the air due to the nonplanar puckered (buckled) structure. Another critical problem is that silicene is usually synthesized by epitaxial growth on a substrate, which strongly affects the π conjugated system of silicene. The fabrication of free-standing silicene with a planar configuration has long been pursued. Here, we report the strategy and design to realize the flat zigzag silicene nanoribbon. We theoretically investigated the stability of various silicene nanoribbons with substituents at the zigzag edges and found that zigzag silicene nanoribbons with beryllium (Be) bridges are very stable in a planar configuration. The obtained zigzag silicene nanoribbon has an indirect negative band gap and is nonmagnetic unlike the magnetic buckled silicene nanoribbons with zigzag edges. The linearly dispersive behavior of the π and π* bands associated with the out-of-plane 3psi and 2pBe orbitals is clearly observed, showing the existence of a Dirac point slightly above the Fermi level. We also observed that spin-orbit coupling induces a gap opening at the Dirac point.
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10
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Zhao M, Zhuang J, Cheng Q, Hao W, Du Y. Moiré-Potential-Induced Band Structure Engineering in Graphene and Silicene. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e1903769. [PMID: 31531941 DOI: 10.1002/smll.201903769] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/29/2019] [Indexed: 05/22/2023]
Abstract
A moiré pattern results from the projection of one periodic pattern to another with relative lattice constant or misalignment and provides great periodic potential to modify the electronic properties of pristine materials. In this Review, recent research on the effect of the moiré superlattice on the electronic structures of graphene and silicene, both of which possess a honeycomb lattice, is focused on. The moiré periodic potential is introduced by the interlayer interaction to realize abundant phenomena, including new generation of Dirac cones, emergence of Van Hove singularities (vHs) at the cross point of two sets of Dirac cones, Mott-like insulating behavior at half-filling state, unconventional superconductivity, and electronic Kagome lattice and flat band with nontrivial edge state. The role of interlayer coupling strength, which is determined by twist angle and buckling degree, in these exotic properties is discussed in terms of both the theoretical prediction and experimental measurement, and finally, the challenges and outlook for this field are discussed.
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Affiliation(s)
- Mengting Zhao
- BUAA-UOW Joint Research Centre and School of Physics, Beihang University, Beijing, 100191, P. R. China
- Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW, 2500, Australia
| | - Jincheng Zhuang
- BUAA-UOW Joint Research Centre and School of Physics, Beihang University, Beijing, 100191, P. R. China
| | - Qunfeng Cheng
- BUAA-UOW Joint Research Centre and School of Chemistry, Beihang University, Beijing, 100191, P. R. China
| | - Weichang Hao
- BUAA-UOW Joint Research Centre and School of Physics, Beihang University, Beijing, 100191, P. R. China
| | - Yi Du
- BUAA-UOW Joint Research Centre and School of Physics, Beihang University, Beijing, 100191, P. R. China
- Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW, 2500, Australia
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11
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Bergeron H, Lebedev D, Hersam MC. Polymorphism in Post-Dichalcogenide Two-Dimensional Materials. Chem Rev 2021; 121:2713-2775. [PMID: 33555868 DOI: 10.1021/acs.chemrev.0c00933] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Two-dimensional (2D) materials exhibit a wide range of atomic structures, compositions, and associated versatility of properties. Furthermore, for a given composition, a variety of different crystal structures (i.e., polymorphs) can be observed. Polymorphism in 2D materials presents a fertile landscape for designing novel architectures and imparting new functionalities. The objective of this Review is to identify the polymorphs of emerging 2D materials, describe their polymorph-dependent properties, and outline methods used for polymorph control. Since traditional 2D materials (e.g., graphene, hexagonal boron nitride, and transition metal dichalcogenides) have already been studied extensively, the focus here is on polymorphism in post-dichalcogenide 2D materials including group III, IV, and V elemental 2D materials, layered group III, IV, and V metal chalcogenides, and 2D transition metal halides. In addition to providing a comprehensive survey of recent experimental and theoretical literature, this Review identifies the most promising opportunities for future research including how 2D polymorph engineering can provide a pathway to materials by design.
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Affiliation(s)
- Hadallia Bergeron
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Dmitry Lebedev
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States.,Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.,Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois 60208, United States
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12
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Quantitative determination of atomic buckling of silicene by atomic force microscopy. Proc Natl Acad Sci U S A 2019; 117:228-237. [PMID: 31871150 DOI: 10.1073/pnas.1913489117] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The atomic buckling in 2D "Xenes" (such as silicene) fosters a plethora of exotic electronic properties such as a quantum spin Hall effect and could be engineered by external strain. Quantifying the buckling magnitude with subangstrom precision is, however, challenging, since epitaxially grown 2D layers exhibit complex restructurings coexisting on the surface. Here, we characterize using low-temperature (5 K) atomic force microscopy (AFM) with CO-terminated tips assisted by density functional theory (DFT) the structure and local symmetry of each prototypical silicene phase on Ag(111) as well as extended defects. Using force spectroscopy, we directly quantify the atomic buckling of these phases within 0.1-Å precision, obtaining corrugations in the 0.8- to 1.1-Å range. The derived band structures further confirm the absence of Dirac cones in any of the silicene phases due to the strong Ag-Si hybridization. Our method paves the way for future atomic-scale analysis of the interplay between structural and electronic properties in other emerging 2D Xenes.
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13
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Feng B, Zhou H, Feng Y, Liu H, He S, Matsuda I, Chen L, Schwier EF, Shimada K, Meng S, Wu K. Superstructure-Induced Splitting of Dirac Cones in Silicene. PHYSICAL REVIEW LETTERS 2019; 122:196801. [PMID: 31144949 DOI: 10.1103/physrevlett.122.196801] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Indexed: 06/09/2023]
Abstract
Atomic scale engineering of two-dimensional materials could create devices with rich physical and chemical properties. External periodic potentials can enable the manipulation of the electronic band structures of materials. A prototypical system is (3×3)-silicene/Ag(111), which has substrate-induced periodic modulations. Recent angle-resolved photoemission spectroscopy measurements revealed six Dirac cone pairs at the Brillouin zone boundary of Ag(111), but their origin remains unclear [Proc. Natl. Acad. Sci. USA 113, 14656 (2016)]. We used linear dichroism angle-resolved photoemission spectroscopy, the tight-binding model, and first-principles calculations to reveal that these Dirac cones mainly derive from the original cones at the K (K^{'}) points of free-standing silicene. The Dirac cones of free-standing silicene are split by external periodic potentials that originate from the substrate-overlayer interaction. Our results not only confirm the origin of the Dirac cones in the (3×3)-silicene/Ag(111) system, but also provide a powerful route to manipulate the electronic structures of two-dimensional materials.
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Affiliation(s)
- Baojie Feng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hui Zhou
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ya Feng
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - Hang Liu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shaolong He
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Iwao Matsuda
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Lan Chen
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Eike F Schwier
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - Kenya Shimada
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - Sheng Meng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Kehui Wu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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14
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Molle A, Grazianetti C, Tao L, Taneja D, Alam MH, Akinwande D. Silicene, silicene derivatives, and their device applications. Chem Soc Rev 2018; 47:6370-6387. [PMID: 30065980 DOI: 10.1039/c8cs00338f] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Silicene, the ultimate scaling of a silicon atomic sheet in a buckled honeycomb lattice, represents a monoelemental class of two-dimensional (2D) materials similar to graphene but with unique potential for a host of exotic electronic properties. Nonetheless, there is a lack of experimental studies largely due to the interplay between material degradation and process portability issues. This review highlights the state-of-the-art experimental progress and future opportunities in the synthesis, characterization, stabilization, processing and experimental device examples of monolayer silicene and its derivatives. The electrostatic characteristics of the Ag-removal silicene field-effect transistor exhibit ambipolar charge transport, corroborating with theoretical predictions on Dirac fermions and Dirac cone in the band structure. The electronic structure of silicene is expected to be sensitive to substrate interaction, surface chemistry, and spin-orbit coupling, holding great promise for a variety of novel applications, such as topological bits, quantum sensing, and energy devices. Moreover, the unique allotropic affinity of silicene with single-crystalline bulk silicon suggests a more direct path for the integration with or revolution to ubiquitous semiconductor technology. Both the materials and process aspects of silicene research also provide transferable knowledge to other Xenes like stanene, germanene, phosphorene, and so forth.
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Affiliation(s)
- Alessandro Molle
- Consiglio Nazionale delle Ricerche (CNR), Istituto per la Microelettronica e Microsistemi (IMM), unit of Agrate Brianza, via C. Olivetti 2, 20864 Agrate Brianza, MB, Italy.
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15
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Krawiec M. Functionalization of group-14 two-dimensional materials. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:233003. [PMID: 29708504 DOI: 10.1088/1361-648x/aac149] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The great success of graphene has boosted intensive search for other single-layer thick materials, mainly composed of group-14 atoms arranged in a honeycomb lattice. This new class of two-dimensional (2D) crystals, known as 2D-Xenes, has become an emerging field of intensive research due to their remarkable electronic properties and the promise for a future generation of nanoelectronics. In contrast to graphene, Xenes are not completely planar, and feature a low buckled geometry with two sublattices displaced vertically as a result of the interplay between sp2 and sp3 orbital hybridization. In spite of the buckling, the outstanding electronic properties of graphene governed by Dirac physics are preserved in Xenes too. The buckled structure also has several advantages over graphene. Together with the spin-orbit (SO) interaction it may lead to the emergence of various experimentally accessible topological phases, like the quantum spin Hall effect. This in turn would lead to designing and building new electronic and spintronic devices, like topological field effect transistors. In this regard an important issue concerns the electron energy gap, which for Xenes naturally exists owing to the buckling and SO interaction. The electronic properties, including the magnitude of the energy gap, can further be tuned and controlled by external means. Xenes can easily be functionalized by substrate, chemical adsorption, defects, charge doping, external electric field, periodic potential, in-plane uniaxial and biaxial stress, and out-of-plane long-range structural deformation, to name a few. This topical review explores structural, electronic and magnetic properties of Xenes and addresses the question of their functionalization in various ways, including external factors acting simultaneously. It also points to future directions to be explored in functionalization of Xenes. The results of experimental and theoretical studies obtained so far have many promising features making the 2D-Xene materials important players in the field of future nanoelectronics and spintronics.
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Affiliation(s)
- Mariusz Krawiec
- Institute of Physics, Maria Curie-Sklodowska University, Pl. M. Curie-Skłodowskiej 1, 20-031 Lublin, Poland
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16
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Feng B, Zhang J, Ito S, Arita M, Cheng C, Chen L, Wu K, Komori F, Sugino O, Miyamoto K, Okuda T, Meng S, Matsuda I. Discovery of 2D Anisotropic Dirac Cones. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:1704025. [PMID: 29171690 DOI: 10.1002/adma.201704025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 09/04/2017] [Indexed: 06/07/2023]
Abstract
2D anisotropic Dirac cones are observed in χ3 borophene, a monolayer boron sheet, using high-resolution angle-resolved photoemission spectroscopy. The Dirac cones are centered at the X and X' points. The data also reveal that the hybridization between borophene and Ag(111) is very weak, which explains the preservation of the Dirac cones. As χ3 borophene has been predicated to be a superconductor, the results may stimulate further research interest in the novel physics of borophene, such as the interplay between Cooper pairs and the massless Dirac fermions.
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Affiliation(s)
- Baojie Feng
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima, 739-0046, Japan
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - Jin Zhang
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Suguru Ito
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - Masashi Arita
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima, 739-0046, Japan
| | - Cai Cheng
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Lan Chen
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Kehui Wu
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Fumio Komori
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - Osamu Sugino
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - Koji Miyamoto
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima, 739-0046, Japan
| | - Taichi Okuda
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima, 739-0046, Japan
| | - Sheng Meng
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Iwao Matsuda
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
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17
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Li G, Zhang YY, Guo H, Huang L, Lu H, Lin X, Wang YL, Du S, Gao HJ. Epitaxial growth and physical properties of 2D materials beyond graphene: from monatomic materials to binary compounds. Chem Soc Rev 2018; 47:6073-6100. [DOI: 10.1039/c8cs00286j] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review highlights the recent advances of epitaxial growth of 2D materials beyond graphene.
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Affiliation(s)
- Geng Li
- Institute of Physics & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Yu-Yang Zhang
- Institute of Physics & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- China
- CAS Center for Excellence in Topological Quantum Computation
| | - Hui Guo
- Institute of Physics & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Li Huang
- Institute of Physics & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Hongliang Lu
- Institute of Physics & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Xiao Lin
- Institute of Physics & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- China
- CAS Center for Excellence in Topological Quantum Computation
| | - Ye-Liang Wang
- Institute of Physics & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- China
- CAS Center for Excellence in Topological Quantum Computation
| | - Shixuan Du
- Institute of Physics & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- China
- CAS Center for Excellence in Topological Quantum Computation
| | - Hong-Jun Gao
- Institute of Physics & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- China
- CAS Center for Excellence in Topological Quantum Computation
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18
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Sheng S, Wu JB, Cong X, Li W, Gou J, Zhong Q, Cheng P, Tan PH, Chen L, Wu K. Vibrational Properties of a Monolayer Silicene Sheet Studied by Tip-Enhanced Raman Spectroscopy. PHYSICAL REVIEW LETTERS 2017; 119:196803. [PMID: 29219519 DOI: 10.1103/physrevlett.119.196803] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Indexed: 05/22/2023]
Abstract
Combining ultrahigh sensitivity, spatial resolution, and the capability to resolve chemical information, tip-enhanced Raman spectroscopy (TERS) is a powerful tool to study molecules or nanoscale objects. Here we show that TERS can also be a powerful tool in studying two-dimensional materials. We have achieved a 10^{9} Raman signal enhancement and a 0.5 nm spatial resolution using monolayer silicene on Ag(111) as a prototypical 2D material system. Because of the selective enhancement on Raman modes with vertical vibrational components in TERS, our experiment provides direct evidence of the origination of Raman modes in silicene. Furthermore, the ultrahigh sensitivity of TERS allows us to identify different vibrational properties of silicene phases, which differ only in the bucking direction of the Si-Si bonds. Local vibrational features from defects and domain boundaries in silicene can also be identified.
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Affiliation(s)
- Shaoxiang Sheng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jiang-Bin Wu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Xin Cong
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Wenbin Li
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jian Gou
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Qing Zhong
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Peng Cheng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- School of physical sciences, and College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lan Chen
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Kehui Wu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of physical sciences, and College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
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19
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van Bremen R, Yao Q, Banerjee S, Cakir D, Oncel N, Zandvliet HJW. Intercalation of Si between MoS 2 layers. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:1952-1960. [PMID: 29046843 PMCID: PMC5629401 DOI: 10.3762/bjnano.8.196] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 08/21/2017] [Indexed: 06/07/2023]
Abstract
We report a combined experimental and theoretical study of the growth of sub-monolayer amounts of silicon (Si) on molybdenum disulfide (MoS2). At room temperature and low deposition rates we have found compelling evidence that the deposited Si atoms intercalate between the MoS2 layers. Our evidence relies on several experimental observations: (1) Upon the deposition of Si on pristine MoS2 the morphology of the surface transforms from a smooth surface to a hill-and-valley surface. The lattice constant of the hill-and-valley structure amounts to 3.16 Å, which is exactly the lattice constant of pristine MoS2. (2) The transitions from hills to valleys are not abrupt, as one would expect for epitaxial islands growing on-top of a substrate, but very gradual. (3) I(V) scanning tunneling spectroscopy spectra recorded at the hills and valleys reveal no noteworthy differences. (4) Spatial maps of dI/dz reveal that the surface exhibits a uniform work function and a lattice constant of 3.16 Å. (5) X-ray photo-electron spectroscopy measurements reveal that sputtering of the MoS2/Si substrate does not lead to a decrease, but an increase of the relative Si signal. Based on these experimental observations we have to conclude that deposited Si atoms do not reside on the MoS2 surface, but rather intercalate between the MoS2 layers. Our conclusion that Si intercalates upon the deposition on MoS2 is at variance with the interpretation by Chiappe et al. (Adv. Mater.2014, 26, 2096-2101) that silicon forms a highly strained epitaxial layer on MoS2. Finally, density functional theory calculations indicate that silicene clusters encapsulated by MoS2 are stable.
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Affiliation(s)
- Rik van Bremen
- Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, Netherlands
| | - Qirong Yao
- Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, Netherlands
| | - Soumya Banerjee
- Department of Physics and Astrophysics, University of North Dakota, Grand Forks, ND 58202, USA
| | - Deniz Cakir
- Department of Physics and Astrophysics, University of North Dakota, Grand Forks, ND 58202, USA
| | - Nuri Oncel
- Department of Physics and Astrophysics, University of North Dakota, Grand Forks, ND 58202, USA
| | - Harold J W Zandvliet
- Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500AE Enschede, Netherlands
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20
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Abstract
Silicene is the silicon equivalent of graphene, which is composed of a honeycomb carbon structure with one atom thickness and has attractive characteristics of a perfect two-dimensional π-conjugated sheet. However, unlike flat and highly stable graphene, silicene is relatively sticky and thus unstable due to its puckered or crinkled structure. Flatness is important for stability, and to obtain perfect π-conjugation, electron-donating atoms and molecules should not interact with the π electrons. The structural differences between silicene and graphene result from the differences in their building blocks, flat benzene and chair-form hexasilabenzene. It is crucial to design flat building blocks for silicene with no interactions between the electron donor and π-orbitals. Here, we report the successful design of such building blocks with the aid of density functional theory calculations. Our fundamental concept is to attach substituents that have sp-hybrid orbitals and act as electron donors in a manner that it does not interact with the π orbitals. The honeycomb silicon molecule with BeH at the edge designed according to our concept, clearly shows the same structural, charge distribution and molecular orbital characteristics as the corresponding carbon-based molecule.
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21
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Chen ZG, Wang L, Song Y, Lu X, Luo H, Zhang C, Dai P, Yin Z, Haule K, Kotliar G. Two-Dimensional Massless Dirac Fermions in Antiferromagnetic AFe_{2}As_{2} (A=Ba,Sr). PHYSICAL REVIEW LETTERS 2017; 119:096401. [PMID: 28949552 DOI: 10.1103/physrevlett.119.096401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Indexed: 06/07/2023]
Abstract
We report infrared studies of AFe_{2}As_{2} (A=Ba, Sr), two representative parent compounds of iron-arsenide superconductors, at magnetic fields (B) up to 17.5 T. Optical transitions between Landau levels (LLs) were observed in the antiferromagnetic states of these two parent compounds. Our observation of a sqrt[B] dependence of the LL transition energies, the zero-energy intercepts at B=0 T under the linear extrapolations of the transition energies and the energy ratio (∼2.4) between the observed LL transitions, combined with the linear band dispersions in two-dimensional (2D) momentum space obtained by theoretical calculations, demonstrates the existence of massless Dirac fermions in the antiferromagnet BaFe_{2}As_{2}. More importantly, the observed dominance of the zeroth-LL-related absorption features and the calculated bands with extremely weak dispersions along the momentum direction k_{z} indicate that massless Dirac fermions in BaFe_{2}As_{2} are 2D. Furthermore, we find that the total substitution of the barium atoms in BaFe_{2}As_{2} by strontium atoms not only maintains 2D massless Dirac fermions in this system, but also enhances their Fermi velocity, which supports that the Dirac points in iron-arsenide parent compounds are topologically protected.
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Affiliation(s)
- Zhi-Guo Chen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Luyang Wang
- Institute for Advanced Study, Tsinghua University, Beijing 100084, China
- Sate Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yu Song
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Xingye Lu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Huiqian Luo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chenglin Zhang
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Pengcheng Dai
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Zhiping Yin
- Center of Advanced Quantum Studies and Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Kristjan Haule
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
- DMFT-MatDeLab Center, Upton, New York 11973, USA
| | - Gabriel Kotliar
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
- DMFT-MatDeLab Center, Upton, New York 11973, USA
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22
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Li Z, Zhuang J, Chen L, Ni Z, Liu C, Wang L, Xu X, Wang J, Pi X, Wang X, Du Y, Wu K, Dou SX. Observation of van Hove Singularities in Twisted Silicene Multilayers. ACS CENTRAL SCIENCE 2016; 2:517-21. [PMID: 27610412 PMCID: PMC4999970 DOI: 10.1021/acscentsci.6b00152] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Indexed: 05/24/2023]
Abstract
Interlayer interactions perturb the electronic structure of two-dimensional materials and lead to new physical phenomena, such as van Hove singularities and Hofstadter's butterfly pattern. Silicene, the recently discovered two-dimensional form of silicon, is quite unique, in that silicon atoms adopt competing sp(2) and sp(3) hybridization states leading to a low-buckled structure promising relatively strong interlayer interaction. In multilayer silicene, the stacking order provides an important yet rarely explored degree of freedom for tuning its electronic structures through manipulating interlayer coupling. Here, we report the emergence of van Hove singularities in the multilayer silicene created by an interlayer rotation. We demonstrate that even a large-angle rotation (>20°) between stacked silicene layers can generate a Moiré pattern and van Hove singularities due to the strong interlayer coupling in multilayer silicene. Our study suggests an intriguing method for expanding the tunability of the electronic structure for electronic applications in this two-dimensional material.
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Affiliation(s)
- Zhi Li
- Institute
for Superconducting and Electronic Materials (ISEM), Australian Institute
for Innovative Materials (AIIM), University
of Wollongong, Wollongong, New South Wales 2525, Australia
| | - Jincheng Zhuang
- Institute
for Superconducting and Electronic Materials (ISEM), Australian Institute
for Innovative Materials (AIIM), University
of Wollongong, Wollongong, New South Wales 2525, Australia
| | - Lan Chen
- Institute
of Physics, Chinese Academy of Sciences, Haidian District, Beijing 100080, China
| | - Zhenyi Ni
- State
Key Laboratory of Silicon Materials and Department of Materials Science
and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Chen Liu
- Beijing
Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Li Wang
- Institute
for Superconducting and Electronic Materials (ISEM), Australian Institute
for Innovative Materials (AIIM), University
of Wollongong, Wollongong, New South Wales 2525, Australia
| | - Xun Xu
- Institute
for Superconducting and Electronic Materials (ISEM), Australian Institute
for Innovative Materials (AIIM), University
of Wollongong, Wollongong, New South Wales 2525, Australia
| | - Jiaou Wang
- Beijing
Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Xiaodong Pi
- State
Key Laboratory of Silicon Materials and Department of Materials Science
and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Xiaolin Wang
- Institute
for Superconducting and Electronic Materials (ISEM), Australian Institute
for Innovative Materials (AIIM), University
of Wollongong, Wollongong, New South Wales 2525, Australia
| | - Yi Du
- Institute
for Superconducting and Electronic Materials (ISEM), Australian Institute
for Innovative Materials (AIIM), University
of Wollongong, Wollongong, New South Wales 2525, Australia
| | - Kehui Wu
- Institute
of Physics, Chinese Academy of Sciences, Haidian District, Beijing 100080, China
| | - Shi Xue Dou
- Institute
for Superconducting and Electronic Materials (ISEM), Australian Institute
for Innovative Materials (AIIM), University
of Wollongong, Wollongong, New South Wales 2525, Australia
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