TY - JOUR
T1 - Observation of Reentrant Correlated Insulators and Interaction-Driven Fermi-Surface Reconstructions at One Magnetic Flux Quantum per Moiré Unit Cell in Magic-Angle Twisted Bilayer Graphene
AU - Das, Ipsita
AU - Shen, Cheng
AU - Jaoui, Alexandre
AU - Herzog-Arbeitman, Jonah
AU - Chew, Aaron
AU - Cho, Chang Woo
AU - Watanabe, Kenji
AU - Taniguchi, Takashi
AU - Piot, Benjamin A.
AU - Bernevig, B. Andrei
AU - Efetov, Dmitri K.
N1 - Funding Information:
D. K. E. acknowledges support from the Ministry of Economy and Competitiveness of Spain through the "Severo Ochoa” programme for Centres of Excellence in R and D (SE5-0522), Fundacio Privada Cellex, Fundacio Privada Mir-Puig, the Generalitat de Catalunya through the CERCA programme, funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant No. 852927). B. A. B.’s work was primarily supported by the DOE Grant No. DE-SC0016239, the Schmidt Fund for Innovative Research, Simons Investigator Grant No. 404513, and the Packard Foundation. Z.-D. S. was supported by ONR No. N00014-20-1-2303, NSF-MRSEC No. DMR-1420541, Gordon and Betty Moore Foundation through Grant No. GBMF8685 toward the Princeton theory program. B. A. B. also acknowledges support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No. 101020833). I. D. acknowledges support from the INphINIT “laCaixa” (ID 100010434) programme (LCF/BQ/DI19/11730030). K. W. and T. T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan (Grant No. JPMXP0112101001) and JSPS KAKENHI (Grants No. 19H05790, No. 20H00354, and No. 21H05233).
Publisher Copyright:
© 2022 American Physical Society.
PY - 2022/5/27
Y1 - 2022/5/27
N2 - The discovery of flat bands with nontrivial band topology in magic-angle twisted bilayer graphene (MATBG) has provided a unique platform to study strongly correlated phenomena including superconductivity, correlated insulators, Chern insulators, and magnetism. A fundamental feature of the MATBG, so far unexplored, is its high magnetic field Hofstadter spectrum. Here, we report on a detailed magnetotransport study of a MATBG device in external magnetic fields of up to B=31 T, corresponding to one magnetic flux quantum per moiré unit cell φ0. At φ0, we observe reentrant correlated insulators at a flat band filling factors of ν=+2 and of ν=+3, and interaction-driven Fermi-surface reconstructions at other fillings, which are identified by new sets of Landau levels originating from these. These experimental observations are supplemented by theoretical work that predicts a new set of eight well-isolated flat bands at φ0, of comparable band width, but with different topology than in zero field. Overall, our magnetotransport data reveal a qualitatively new Hofstadter spectrum in MATBG, which arises due to the strong electronic correlations in the reentrant flat bands.
AB - The discovery of flat bands with nontrivial band topology in magic-angle twisted bilayer graphene (MATBG) has provided a unique platform to study strongly correlated phenomena including superconductivity, correlated insulators, Chern insulators, and magnetism. A fundamental feature of the MATBG, so far unexplored, is its high magnetic field Hofstadter spectrum. Here, we report on a detailed magnetotransport study of a MATBG device in external magnetic fields of up to B=31 T, corresponding to one magnetic flux quantum per moiré unit cell φ0. At φ0, we observe reentrant correlated insulators at a flat band filling factors of ν=+2 and of ν=+3, and interaction-driven Fermi-surface reconstructions at other fillings, which are identified by new sets of Landau levels originating from these. These experimental observations are supplemented by theoretical work that predicts a new set of eight well-isolated flat bands at φ0, of comparable band width, but with different topology than in zero field. Overall, our magnetotransport data reveal a qualitatively new Hofstadter spectrum in MATBG, which arises due to the strong electronic correlations in the reentrant flat bands.
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U2 - 10.1103/PhysRevLett.128.217701
DO - 10.1103/PhysRevLett.128.217701
M3 - Article
C2 - 35687461
AN - SCOPUS:85131295892
SN - 0031-9007
VL - 128
JO - Physical review letters
JF - Physical review letters
IS - 21
M1 - 217701
ER -