Dirac spectroscopy of strongly correlated phases in twisted trilayer graphene

Shen, Cheng; Ledwith, Patrick J.; Watanabe, Kenji; Taniguchi, Takashi; Khalaf, Eslam; Vishwanath, Ashvin und Efetov, Dmitri K. (2022): Dirac spectroscopy of strongly correlated phases in twisted trilayer graphene. In: Nature Materials, Bd. 22, Nr. 3: S. 316-321

Abstract

Magic-angle twisted trilayer graphene (MATTG) hosts flat electronic bands, and exhibits correlated quantum phases with electrical tunability. In this work, we demonstrate a spectroscopy technique that allows for dissociation of intertwined bands and quantification of the energy gaps and Chern numbers C of the correlated states in MATTG by driving band crossings between Dirac cone Landau levels and energy gaps in the flat bands. We uncover hard correlated gaps with C = 0 at integer moir & eacute;unit cell fillings of v = 2 and 3 and reveal charge density wave states originating from van Hove singularities at fractional fillings v = 5/3 and 11/3. In addition, we demonstrate displacement-field-driven first-order phase transitions at charge neutrality and v = 2, which are consistent with a theoretical strong-coupling analysis, implying C(2)Tsymmetry breaking. Overall, these properties establish a diverse electrically tunable phase diagram of MATTG and provide an avenue for investigating other related systems hosting both steep and flat bands.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• ISSN: 1476-1122
• Sprache: Englisch