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Shaping the Topology of Twisted Bilayer Graphene via Time-reversal Symmetry Breaking by Jiang, Cunyuan; Baggioli, Matteo; Jiang, Qing-Dong is a scholarly article available to read on EtoBox.

What is Shaping the Topology of Twisted Bilayer Graphene via Time-reversal Symmetry Breaking about?

Symmetry breaking is an effective tool for tuning the transport and topological properties of 2D layered materials. Among these materials, twisted bilayer graphene (TBG) has emerged as a promising platform for new physics, characterized by a rich interplay between topological features and strongly correlated electronic behavior. In this study, we utilize time-reversal symmetry breaking (TRSB) to manipulate the topological properties of TBG. By varying the strength of TRSB, we discover a topological phase transition between a topological insulating phase, which exhibits a pair of flat bands with opposite Chern numbers, and a novel insulating state where the Chern number, but not the Berry curvature, of the flat bands vanishes. We demonstrate that this topological transition is mediated by a gap closing at the $\Gamma$ point, and we construct a three-dimensional phase diagram as a function of the twisting angle, the symmetry-breaking parameter, and the mismatch coupling between AA and AB stacking regions. Finally, we show that this novel electronic phase can be identified in the lab by measuring, as a function of the Fermi energy, its non-quantized anomalous Hall conductivity that is

Author

Jiang, Cunyuan; Baggioli, Matteo; Jiang, Qing-Dong

Published

2024

Language

EN