Observation of Reentrant Correlated Insulators and Interaction-Driven Fermi-Surface Reconstructions at One Magnetic Flux Quantum per Moire? Unit Cell in Magic-Angle Twisted Bilayer Graphene

被引：29

作者：

Das, Ipsita ^{[1
]}

Shen, Cheng ^{[1
]}

Jaoui, Alexandre ^{[1
]}

Herzog-Arbeitman, Jonah ^{[2
]}

Chew, Aaron ^{[2
]}

Cho, Chang-Woo ^{[3
]}

Watanabe, Kenji ^{[4
]}

Taniguchi, Takashi ^{[5
]}

Piot, Benjamin A. ^{[3
]}

Bernevig, B. Andrei ^{[2
]}

Efetov, Dmitri K. ^{[1
]}

机构：

[1] Barcelona Inst Sci & Technol, ICFO Inst Ciencies Foton, Barcelona 08860, Spain

[2] Princeton Univ, Dept Phys, Princeton, NJ 08544 USA

[3] Univ Grenoble Alpes, Lab Natl Champs Magnet Intens, UPS INSA EMFL CNRS LNCMI, 25 Ave Martyrs, F-38042 Grenoble, France

[4] Natl Inst Mat Sci, Funct Mat Res Ctr, 1-1 Namiki, Tsukuba, Ibaraki 3050044, Japan

[5] Natl Inst Mat Sci, Int Ctr Mat Nanoarchitecton, 1-1 Namiki, Tsukuba, Ibaraki 3050044, Japan

来源：

PHYSICAL REVIEW LETTERS | 2022年 / 128卷 / 21期

基金：

欧洲研究理事会;

关键词：

DIRAC FERMIONS; TRANSITIONS; CASCADE;

D O I：

10.1103/PhysRevLett.128.217701

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

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 moire??unit cell 00. At 00, we observe reentrant correlated insulators at a flat band filling factors of ?? = +2 and of ?? = +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 00, 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.

引用

页数：6