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Vizner Stern M, Waschitz Y, Cao W, Nevo I, Watanabe K, Taniguchi T, Sela E, Urbakh M, Hod O, Ben Shalom M. Interfacial ferroelectricity by van der Waals sliding. Science 2021; 372:eabe8177. [PMID: 34112727 DOI: 10.1126/science.abe8177] [Citation(s) in RCA: 122] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 05/10/2021] [Indexed: 12/14/2022]
Abstract
Despite their partial ionic nature, many layered diatomic crystals avoid internal electric polarization by forming a centrosymmetric lattice at their optimal van-der-Waals stacking. Here, we report a stable ferroelectric order emerging at the interface between two naturally-grown flakes of hexagonal-boron-nitride, which are stacked together in a metastable non-centrosymmetric parallel orientation. We observe alternating domains of inverted normal polarization, caused by a lateral shift of one lattice site between the domains. Reversible polarization switching coupled to lateral sliding is achieved by scanning a biased tip above the surface. Our calculations trace the origin of the phenomenon to a subtle interplay between charge redistribution and ionic displacement, and provide intuitive insights to explore the interfacial polarization and its unique "slidetronics" switching mechanism.
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Affiliation(s)
- M Vizner Stern
- School of Physics and Astronomy, Tel Aviv University, Israel
| | - Y Waschitz
- School of Physics and Astronomy, Tel Aviv University, Israel
| | - W Cao
- Department of Physical Chemistry, School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 6997801, Israel
| | - I Nevo
- School of Physics and Astronomy, Tel Aviv University, Israel
| | - K Watanabe
- National Institute for Material Science, Tsukuba, Japan
| | - T Taniguchi
- National Institute for Material Science, Tsukuba, Japan
| | - E Sela
- School of Physics and Astronomy, Tel Aviv University, Israel
| | - M Urbakh
- Department of Physical Chemistry, School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 6997801, Israel
| | - O Hod
- Department of Physical Chemistry, School of Chemistry, The Raymond and Beverly Sackler Faculty of Exact Sciences and The Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 6997801, Israel
| | - M Ben Shalom
- School of Physics and Astronomy, Tel Aviv University, Israel.
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2
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Berdyugin AI, Xu SG, Pellegrino FMD, Krishna Kumar R, Principi A, Torre I, Ben Shalom M, Taniguchi T, Watanabe K, Grigorieva IV, Polini M, Geim AK, Bandurin DA. Measuring Hall viscosity of graphene's electron fluid. Science 2019; 364:162-165. [PMID: 30819929 DOI: 10.1126/science.aau0685] [Citation(s) in RCA: 128] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 02/19/2019] [Indexed: 01/22/2023]
Abstract
An electrical conductor subjected to a magnetic field exhibits the Hall effect in the presence of current flow. Here, we report a qualitative deviation from the standard behavior in electron systems with high viscosity. We found that the viscous electron fluid in graphene responds to nonquantizing magnetic fields by producing an electric field opposite to that generated by the ordinary Hall effect. The viscous contribution is substantial and identified by studying local voltages that arise in the vicinity of current-injecting contacts. We analyzed the anomaly over a wide range of temperatures and carrier densities and extracted the Hall viscosity, a dissipationless transport coefficient that was long identified theoretically but remained elusive in experiments.
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Affiliation(s)
- A I Berdyugin
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - S G Xu
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - F M D Pellegrino
- Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia, 64, I-95123 Catania, Italy.,Istituto Nazionale di Fisica Nucleare, Sez. Catania, I-95123 Catania, Italy
| | - R Krishna Kumar
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - A Principi
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - I Torre
- ICFO-Institut de Ciències Fotòniques, Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - M Ben Shalom
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - T Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
| | - K Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
| | - I V Grigorieva
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - M Polini
- Istituto Italiano di Tecnologia, Graphene Labs, Via Morego 30, 16163 Genova, Italy.,School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - A K Geim
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK. .,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - D A Bandurin
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.
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3
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Krishna Kumar R, Chen X, Auton GH, Mishchenko A, Bandurin DA, Morozov SV, Cao Y, Khestanova E, Ben Shalom M, Kretinin AV, Novoselov KS, Eaves L, Grigorieva IV, Ponomarenko LA, Fal'ko VI, Geim AK. High-temperature quantum oscillations caused by recurring Bloch states in graphene superlattices. Science 2018; 357:181-184. [PMID: 28706067 DOI: 10.1126/science.aal3357] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 06/09/2017] [Indexed: 11/03/2022]
Abstract
Cyclotron motion of charge carriers in metals and semiconductors leads to Landau quantization and magneto-oscillatory behavior in their properties. Cryogenic temperatures are usually required to observe these oscillations. We show that graphene superlattices support a different type of quantum oscillation that does not rely on Landau quantization. The oscillations are extremely robust and persist well above room temperature in magnetic fields of only a few tesla. We attribute this phenomenon to repetitive changes in the electronic structure of superlattices such that charge carriers experience effectively no magnetic field at simple fractions of the flux quantum per superlattice unit cell. Our work hints at unexplored physics in Hofstadter butterfly systems at high temperatures.
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Affiliation(s)
- R Krishna Kumar
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK.,Department of Physics, University of Lancaster, Lancaster LA1 4YW, UK
| | - X Chen
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - G H Auton
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - A Mishchenko
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - D A Bandurin
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - S V Morozov
- Institute of Microelectronics Technology and High Purity Materials, Russian Academy of Sciences, Chernogolovka 142432, Russia.,National University of Science and Technology (MISiS), Moscow 119049, Russia
| | - Y Cao
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - E Khestanova
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - M Ben Shalom
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - A V Kretinin
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK.,School of Materials, University of Manchester, Manchester M13 9PL, UK
| | - K S Novoselov
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - L Eaves
- National Graphene Institute, University of Manchester, Manchester M13 9PL, UK.,School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - I V Grigorieva
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
| | - L A Ponomarenko
- Department of Physics, University of Lancaster, Lancaster LA1 4YW, UK
| | - V I Fal'ko
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK. .,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
| | - A K Geim
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK. .,National Graphene Institute, University of Manchester, Manchester M13 9PL, UK
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Woods CR, Withers F, Zhu MJ, Cao Y, Yu G, Kozikov A, Ben Shalom M, Morozov SV, van Wijk MM, Fasolino A, Katsnelson MI, Watanabe K, Taniguchi T, Geim AK, Mishchenko A, Novoselov KS. Macroscopic self-reorientation of interacting two-dimensional crystals. Nat Commun 2016; 7:10800. [PMID: 26960435 PMCID: PMC4792927 DOI: 10.1038/ncomms10800] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 01/20/2016] [Indexed: 11/16/2022] Open
Abstract
Microelectromechanical systems, which can be moved or rotated with nanometre precision, already find applications in such fields as radio-frequency electronics, micro-attenuators, sensors and many others. Especially interesting are those which allow fine control over the motion on the atomic scale because of self-alignment mechanisms and forces acting on the atomic level. Such machines can produce well-controlled movements as a reaction to small changes of the external parameters. Here we demonstrate that, for the system of graphene on hexagonal boron nitride, the interplay between the van der Waals and elastic energies results in graphene mechanically self-rotating towards the hexagonal boron nitride crystallographic directions. Such rotation is macroscopic (for graphene flakes of tens of micrometres the tangential movement can be on hundreds of nanometres) and can be used for reproducible manufacturing of aligned van der Waals heterostructures.
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Affiliation(s)
- C. R. Woods
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - F. Withers
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - M. J. Zhu
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Y. Cao
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - G. Yu
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - A. Kozikov
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - M. Ben Shalom
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - S. V. Morozov
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- Institute of Microelectronics Technology and High Purity Materials RAS, Chernogolovka 142432, Russia
- National University of Science and Technology ‘MISiS', Moscow 119049, Russia
| | - M. M. van Wijk
- Institute for Molecules and Materials,Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - A. Fasolino
- Institute for Molecules and Materials,Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - M. I. Katsnelson
- Institute for Molecules and Materials,Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - K. Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - T. Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - A. K. Geim
- Centre for Mesoscience and Nanotechnology, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - A. Mishchenko
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - K. S. Novoselov
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
- National Graphene Institute, University of Manchester, Oxford Road, Manchester M13 9PL, UK
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5
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Bandurin DA, Torre I, Kumar RK, Ben Shalom M, Tomadin A, Principi A, Auton GH, Khestanova E, Novoselov KS, Grigorieva IV, Ponomarenko LA, Geim AK, Polini M. Negative local resistance caused by viscous electron backflow in graphene. Science 2016; 351:1055-8. [DOI: 10.1126/science.aad0201] [Citation(s) in RCA: 415] [Impact Index Per Article: 51.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 12/23/2015] [Indexed: 01/22/2023]
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6
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Cao Y, Mishchenko A, Yu GL, Khestanova E, Rooney AP, Prestat E, Kretinin AV, Blake P, Shalom MB, Woods C, Chapman J, Balakrishnan G, Grigorieva IV, Novoselov KS, Piot BA, Potemski M, Watanabe K, Taniguchi T, Haigh SJ, Geim AK, Gorbachev RV. Quality Heterostructures from Two-Dimensional Crystals Unstable in Air by Their Assembly in Inert Atmosphere. Nano Lett 2015; 15:4914-4921. [PMID: 26132110 DOI: 10.1021/acs.nanolett.5b00648] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Many layered materials can be cleaved down to individual atomic planes, similar to graphene, but only a small minority of them are stable under ambient conditions. The rest react and decompose in air, which has severely hindered their investigation and potential applications. Here we introduce a remedial approach based on cleavage, transfer, alignment, and encapsulation of air-sensitive crystals, all inside a controlled inert atmosphere. To illustrate the technology, we choose two archetypal two-dimensional crystals that are of intense scientific interest but are unstable in air: black phosphorus and niobium diselenide. Our field-effect devices made from their monolayers are conductive and fully stable under ambient conditions, which is in contrast to the counterparts processed in air. NbSe2 remains superconducting down to the monolayer thickness. Starting with a trilayer, phosphorene devices reach sufficiently high mobilities to exhibit Landau quantization. The approach offers a venue to significantly expand the range of experimentally accessible two-dimensional crystals and their heterostructures.
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Affiliation(s)
| | | | | | | | | | | | | | - P Blake
- ∥Graphene Industries Ltd., 2 Tupelo Street, Manchester, M13 9HQ, United Kingdom
| | | | | | | | - G Balakrishnan
- ⊥Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | | | | | - B A Piot
- #Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, F-38042 Grenoble, France
| | - M Potemski
- #Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA, F-38042 Grenoble, France
| | - K Watanabe
- ∇National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
| | - T Taniguchi
- ∇National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
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7
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Salman Z, Ofer O, Radovic M, Hao H, Ben Shalom M, Chow KH, Dagan Y, Hossain MD, Levy CDP, Macfarlane WA, Morris GM, Patthey L, Pearson MR, Saadaoui H, Schmitt T, Wang D, Kiefl RF. Nature of weak magnetism in SrTiO3/LaAlO3 multilayers. Phys Rev Lett 2012; 109:257207. [PMID: 23368496 DOI: 10.1103/physrevlett.109.257207] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 09/20/2012] [Indexed: 06/01/2023]
Abstract
We report the observation of weak magnetism in superlattices of LaAlO(3)/SrTiO(3) using β-detected nuclear magnetic resonance. The spin lattice relaxation rate of ^{8}Li in superlattices with a spacer layers of 8 and 6 unit cells of LaAlO(3) exhibits a strong peak near ~35 K, whereas no such peak is observed in a superlattice with spacer layer thickness of 3 unit cells. We attribute the observed temperature dependence to slowing down of weakly coupled electronic moments at the LaAlO(3)/SrTiO(3) interface. These results show that the magnetism at the interface depends strongly on the thickness of the spacer layer, and that a minimal thickness of ~4-6 unit cells is required for the appearance of magnetism. A simple model is used to determine that the observed relaxation is due to small fluctuating moments (~0.002μ(B)) in the two samples with a larger LaAlO(3) spacer thickness.
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Affiliation(s)
- Z Salman
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
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8
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Abstract
Quantum magnetic oscillations in SrTiO3/LaAlO3 interface are observed in the magnetoresistance. We study their frequency as a function of gate voltage and the evolution of their amplitude with temperature. The data are consistent with the Shubnikov-de Haas theory. The Hall resistivity ρ(xy) is nonlinear at low magnetic fields. ρ(xy) is fitted assuming multiple carrier contributions. We infer the density of the mobile charge carriers from the oscillations frequency and from Hall measurements. The comparison between these densities suggests multiple valley and spin degeneracy. The small amplitude of the oscillation is discussed in the framework of the multiple band scenario.
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Affiliation(s)
- M Ben Shalom
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, Tel Aviv, 69978, Israel
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Ben Shalom M, Sachs M, Rakhmilevitch D, Palevski A, Dagan Y. Tuning spin-orbit coupling and superconductivity at the SrTiO{3}/LaAlO{3} interface: a magnetotransport study. Phys Rev Lett 2010; 104:126802. [PMID: 20366556 DOI: 10.1103/physrevlett.104.126802] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Indexed: 05/29/2023]
Abstract
The superconducting transition temperature T{c} of the SrTiO{3}/LaAlO{3} interface was varied by the electric field effect. The anisotropy of the upper critical field and the normal-state magnetotransport were studied as a function of gate voltage. The spin-orbit coupling energy epsilon{SO} is extracted. This tunable energy scale is used to explain the strong gate dependence of the mobility and of the anomalous Hall signal observed. Epsilon{SO} follows T{c} for the electric field range under study.
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Affiliation(s)
- M Ben Shalom
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, Tel Aviv, 69978, Israel
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