This lifts both the sublattice and the spin degeneracy, while the QH states at ν=±4 can be attributed to lifting of the spin degeneracy of the LLs. Apart from any fair dealing for the purpose of private study or research, no further investigated the screening effects and short-range lattice-scale contributions of the Coulomb and electron-phonon interactions to determine the energetically favorable ground state. By using our site, you acknowledge that you have read and understand our Privacy Policy In a MOSFET, conduction electrons travel in a thin surface layer, and a "gate" voltage controls the number of charge carriers in this layer. Materials that exhibit topological phases can be classified by their dimensionality, symmetries and topological invariants to form conductive-edge states with peculiar transport and spin properties. Export citation and abstract This document is subject to copyright. If you have a user account, you will need to reset your password the next time you login. To overcome this, scientists had previously applied a very strong in-plane magnetic field component higher than 30 Tesla to surpass anisotropic interactions, allowing the F-phase to experimentally emerge in graphene. For instance, the Coulomb energy scale could be enhanced by increasing the magnetic field to induce a topological quantum phase transition from the QHTI (quantum Hall topological insulators) ferromagnetic phase to an insulating, trivial quantum Hall ground state—a type of transition hitherto little addressed. Published 11 January 2012, Yafis Barlas et al 2012 Nanotechnology 23 052001, https://doi.org/10.1088/0957-4484/23/5/052001. Copyright © 2020 Elsevier B.V. or its licensors or contributors. Javier D. Sanchez-Yamagishi et al. Instead of boosting the Zeeman energy or Zeeman effect i.e. We consider an infinite graphene sheet with weak disorder that leads to broadening of Landau levels. When distinct characteristics of quantum Hall systems are compared with time-reversal symmetric (entropy conserved) topological insulators (TIs), they appear to rely on Coulomb interactions between electrons to induce a wealth of strongly correlated, topologically or symmetry-projected phases in a variety of experimental systems. The setup eventually modified the ground state of graphene at charge neutrality. We do not guarantee individual replies due to extremely high volume of correspondence. Institutional subscribers have access to the current volume, plus a For example, the quantum Hall effect can arise in two-dimensional (2-D) electron systems subjected to a perpendicular magnetic field. RIS. Purchase this article from our trusted document delivery partners. Get weekly and/or daily updates delivered to your inbox. also observed simultaneous measurements of two-terminal resistances and non-local resistance while keeping the same source and drain current-injection contacts to demonstrate current flow on the edges of the sample. Veyrat et al. Quantum anomalous Hall (QAH) effect, with potential applications in low-power-consumption electronics, is predicted in the heterostructure of graphene on the (001) surface of a real antiferromagnetic insulator RbMnCl3, based on density-functional theory and Wannier function methods. You can be assured our editors closely monitor every feedback sent and will take appropriate actions. We explain why graphene and bilayer graphene can be viewed respectively as J = 1 and 2 chiral two-dimensional electron gases (C2DEGs), and why this property frames their quantum Hall physics. DOI: 10.1038/nature12800, More from High Energy, Nuclear, Particle Physics. What are some example Feynman diagrams in Yang-Mills theory? DOI: 10.1038/nnano.2016.214, A. F. Young et al. You can unsubscribe at any time and we'll never share your details to third parties. We use cookies to help provide and enhance our service and tailor content and ads. The QSH plateau of conductance e2 /h clearly emerges at charge neutrality around Vbg = … Special attention is given to the interesting low magnetic field limit, and to the relationship between quantum Hall effects and the spontaneous anomalous Hall effects that might occur in bilayer graphene systems in the absence of a magnetic field. To investigate robustness of helical edge transport, the team conducted systematic studies of its temperature and magnetic field dependence. The method of substrate-screening engineering was tunable due to the thickness of the hBN spacer used in the study, the team therefore expect the ground states and optoelectronic properties of other correlated 2-D systems to be as strongly influenced by their dielectric environment. The computer you are using is not registered by an institution with a subscription to this article. Form and we will follow up with your librarian or Institution on your behalf. Thank you for taking your time to send in your valued opinion to Science X editors. Helical edge states and fractional quantum Hall effect in a graphene electron–hole bilayer, Nature Nanotechnology (2016). You do not need to reset your password if you login via Athens or an Institutional login. The recent isolation of graphene [14, 15], a two-dimensional honeycomb lattice of carbon atoms, has enabled exploration [16–18] of the quantum Hall effect, along with many other electronic properties, in a 2DEG that has a thickness of one atomic layer and is qualitatively distinct. Known quantum Hall systems involve electrons near band edges that can be described using k⋅p continuum models in which the lattice constant length scale plays no role. “Half-integer” Quantum Hall Effect Single-layer graphene: QHE plateaus observed at Landau level spectrum with very high cyclotron energy (1000K) To understand the limit of quantized helical edge transport, the team measured different contact configurations at several magnetic field and temperature values to show that quantized helical edge transport could withstand very high temperatures of up to 110 K. The team then demonstrated the key role of the SrTiO3 dielectric substrate during F-phase establishment.

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