Bridging Hubbard model physics and quantum Hall physics in trilayer graphene / h − BN moiré superlattice

© 2019 American Physical Society. The moiré superlattice formed by ABC stacked trilayer graphene aligned with a hexagonal boron nitride substrate (TG/h-BN) provides an interesting system where both the bandwidth and the topology can be tuned by an applied perpendicular electric field D. Thus the TG/...

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Main Authors: Zhang, Ya-Hui, Senthil, T
Format: Article
Language:English
Published: American Physical Society (APS) 2021
Online Access:https://hdl.handle.net/1721.1/134810
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author Zhang, Ya-Hui
Senthil, T
author_facet Zhang, Ya-Hui
Senthil, T
author_sort Zhang, Ya-Hui
collection MIT
description © 2019 American Physical Society. The moiré superlattice formed by ABC stacked trilayer graphene aligned with a hexagonal boron nitride substrate (TG/h-BN) provides an interesting system where both the bandwidth and the topology can be tuned by an applied perpendicular electric field D. Thus the TG/h-BN system can simulate both Hubbard model physics and nearly flat Chern band physics within one sample. We derive lattice models for both signs of D (which controls the band topology) separately through explicit Wannier orbital construction and mapping of Coulomb interaction. When the bands are topologically trivial, we discuss possible candidates for Mott insulators at integer number of holes per site (labeled as νT). These include both broken symmetry states and quantum spin liquid insulators which may be particularly favorable in the vicinity of the Mott transition. We propose feasible experiments to study carefully the bandwidth tuned and the doping tuned Mott metal-insulator transition at both νT=1 and νT=2. We discuss the interesting possibility of probing experimentally a bandwidth (or doping) controlled continuous Mott transition between a Fermi liquid metal and a quantum spin liquid insulator. Finally we also show that the system has a large valley Zeeman coupling to a small out-of-plane magnetic field, which can be used to control the valley degree of freedom.
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spelling mit-1721.1/1348102021-10-28T03:13:12Z Bridging Hubbard model physics and quantum Hall physics in trilayer graphene / h − BN moiré superlattice Zhang, Ya-Hui Senthil, T © 2019 American Physical Society. The moiré superlattice formed by ABC stacked trilayer graphene aligned with a hexagonal boron nitride substrate (TG/h-BN) provides an interesting system where both the bandwidth and the topology can be tuned by an applied perpendicular electric field D. Thus the TG/h-BN system can simulate both Hubbard model physics and nearly flat Chern band physics within one sample. We derive lattice models for both signs of D (which controls the band topology) separately through explicit Wannier orbital construction and mapping of Coulomb interaction. When the bands are topologically trivial, we discuss possible candidates for Mott insulators at integer number of holes per site (labeled as νT). These include both broken symmetry states and quantum spin liquid insulators which may be particularly favorable in the vicinity of the Mott transition. We propose feasible experiments to study carefully the bandwidth tuned and the doping tuned Mott metal-insulator transition at both νT=1 and νT=2. We discuss the interesting possibility of probing experimentally a bandwidth (or doping) controlled continuous Mott transition between a Fermi liquid metal and a quantum spin liquid insulator. Finally we also show that the system has a large valley Zeeman coupling to a small out-of-plane magnetic field, which can be used to control the valley degree of freedom. 2021-10-27T20:09:17Z 2021-10-27T20:09:17Z 2019 2021-06-23T12:23:08Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/134810 en 10.1103/PHYSREVB.99.205150 Physical Review B Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Physical Society (APS) APS
spellingShingle Zhang, Ya-Hui
Senthil, T
Bridging Hubbard model physics and quantum Hall physics in trilayer graphene / h − BN moiré superlattice
title Bridging Hubbard model physics and quantum Hall physics in trilayer graphene / h − BN moiré superlattice
title_full Bridging Hubbard model physics and quantum Hall physics in trilayer graphene / h − BN moiré superlattice
title_fullStr Bridging Hubbard model physics and quantum Hall physics in trilayer graphene / h − BN moiré superlattice
title_full_unstemmed Bridging Hubbard model physics and quantum Hall physics in trilayer graphene / h − BN moiré superlattice
title_short Bridging Hubbard model physics and quantum Hall physics in trilayer graphene / h − BN moiré superlattice
title_sort bridging hubbard model physics and quantum hall physics in trilayer graphene h bn moire superlattice
url https://hdl.handle.net/1721.1/134810
work_keys_str_mv AT zhangyahui bridginghubbardmodelphysicsandquantumhallphysicsintrilayergraphenehbnmoiresuperlattice
AT senthilt bridginghubbardmodelphysicsandquantumhallphysicsintrilayergraphenehbnmoiresuperlattice