Tunable van Hove singularities and correlated states in twisted monolayer–bilayer graphene

Xu, Shuigang; Al Ezzi, Mohammed M.; Balakrishnan, Nilanthy; Garcia-Ruiz, Aitor; Tsim, Bonnie; Mullan, Ciaran; Barrier, Julien; Xin, Na; Piot, Benjamin A.; Taniguchi, Takashi; Watanabe, Kenji; Carvalho, Alexandra; Mishchenko, Artem; Geim, A.K.; Fal’ko, Vladimir I.; Adam, Shaffique; Castro Neto, Antonio Helio; Novoselov, Kostya S.; Shi, Yanmeng

Abstract

Understanding and tuning correlated states is of great interest and significance to modern condensed matter physics. The recent discovery of unconventional superconductivity and Mott-like insulating states in magic-angle twisted bilayer graphene (tBLG) presents a unique platform to study correlation phenomena, in which the Coulomb energy dominates over the quenched kinetic energy as a result of hybridized flat bands. Extending this approach to the case of twisted multilayer graphene would allow even higher control over the band structure because of the reduced symmetry of the system. Here, we study electronic transport properties in twisted trilayer graphene (tTLG, bilayer on top of monolayer graphene heterostructure). We observed the formation of van Hove singularities which are highly tunable by twist angle and displacement field and can cause strong correlation effects under optimum conditions, including superconducting states. We provide basic theoretical interpretation of the observed electronic structure.

Citation

Xu, S., Al Ezzi, M. M., Balakrishnan, N., Garcia-Ruiz, A., Tsim, B., Mullan, C., Barrier, J., Xin, N., Piot, B. A., Taniguchi, T., Watanabe, K., Carvalho, A., Mishchenko, A., Geim, A., Fal’ko, V. I., Adam, S., Castro Neto, A. H., Novoselov, K. S., & Shi, Y. (2021). Tunable van Hove singularities and correlated states in twisted monolayer–bilayer graphene. Nature Physics, 17, 619–626. https://doi.org/10.1038/s41567-021-01172-9

• Journal Article Type: Article
• Acceptance Date: Jan 8, 2021
• Online Publication Date: Feb 18, 2021
• Publication Date: 2021-05
• Journal: Nature Physics
• Print ISSN: 1745-2473
• Electronic ISSN: 1745-2481
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 17
• Pages: 619–626
• DOI: https://doi.org/10.1038/s41567-021-01172-9
• Public URL: https://keele-repository.worktribe.com/output/419253
• Publisher URL: https://www.nature.com/articles/s41567-021-01172-9