Symmetry breaking and Chern insulators in twisted graphene structures

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Chern insulators in twisted graphene
2021. 11. 26. 10:15
BME building F, seminar room of the Dept. of Theoretical Physics
Louk Rademaker (Geneve)
Talk also broadcasted online in Teams. Please write to for the Teams link.  
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, I will show that many of the observed interacting phenomena can be explained in terms of breaking of spin/valley symmetry. This can lead to a quantum anomalous Hall effect in the absence of a field, as I will show for tMBG [1]. In large magnetic fields the same spin- valley symmetry breaking leads to a series of Chern insulator states [2]. Finally, I will briefly discuss the possibility of genuine strong correlated physics in Moiré structures.
[1] Rademaker, Protopopov, Abanin, Phys. Rev. Research, 2, 033150 (2020).
[2] Saito, Ge, Rademaker, Watanabe, Taniguchi, Abanin, Young, Nature Physics, 108, 12233 (2021).