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 - 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 -