Details

Autor(en) / Beteiligte

• Das, Ipsita
• Shen, Cheng
• Jaoui, Alexandre
• Herzog-Arbeitman, Jonah
• Chew, Aaron
• Cho, Chang-Woo
• Watanabe, Kenji
• Taniguchi, Takashi
• Piot, Benjamin A
• Bernevig, B Andrei
• Efetov, Dmitri K

Titel

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

Ist Teil von

• Physical review letters, 2022-05, Vol.128 (21), p.217701-217701, Article 217701

Ort / Verlag

United States: American Physical Society

Erscheinungsjahr

2022

Quelle

American Physical Society

Beschreibungen/Notizen

• 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 Φ_{0}. At Φ_{0}, 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 Φ_{0}, 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.