др Лук Радемакер

11. априла 2022.

У оквиру семинара Центра за изучавање комплексних система Института за физику у Београду, у четвртак, 14. априла 2022. године у 14 часова путем Zoom платформе, др Лук Радемакер (Департман за теоријску физику, Универзитет у Женеви), одржаће предавање:

Symmetry breaking and Chern insulators in twisted graphene structures


Twisted bilayer graphene (tBG) and variants like twisted monolayer-bilayer graphene (tMBG) were proposed to be a platform for strongly correlated physics akin to the cuprate family. However, we will show that many of the observed interacting phenomena can be explained in terms of breaking of spin/valley symmetry. To do so, we will first describe how flat bands in tBG can be directly observed using ARPES [1]. An effective description of the flat bands is hampered by band renormalization due to charge transfer [2] and band topology. The combination of interactions and topology naturally leads to spin/valley symmetry breaking with a quantum anomalous Hall effect in tMBG [3]. In tBG in large magnetic fields, similar spin/valley symmetry breaking creates a series of Chern insulator states [4]. We will conclude with a brief discussion of the possibility of genuine strong correlations in Moiré structures.

[1] S. Lisi, X. Lu, T. Benschop, et al., Nature Phys. 17, 189 (2021).
[2] L. Rademaker, D. A. Abanin, P. Mellado, Phys. Rev. B 100, 205114 (2019).
[3] L. Rademaker, I. V. Protopopov, D. A. Abanin, Phys. Rev. Research 2, 033150 (2020).
[4] Y. Saito, J. Ge, L. Rademaker, et al., Nat. Phys. 17, 478 (2021).

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Meeting ID: 897 1269 4555
Passcode: 580212