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Interplay of Valley, Layer and Band Topology Towards Interacting Quantum Phases in Moir\'e Bilayer Graphene by Jeong, Yungi; Park, Hangyeol; Kim, Taeho; Watanabe, Kenji; Taniguchi, Takashi; Jung, Jeil; Jang, Joonho is a scholarly article available to read on EtoBox.

What is Interplay of Valley, Layer and Band Topology Towards Interacting Quantum Phases in Moir\'e Bilayer Graphene about?

In Bernal-stacked bilayer graphene (BBG), the Landau levels give rise to an intimate connection between valley and layer degrees of freedom. Adding a moir\'e superlattice potential enriches the BBG physics with the formation of topological minibands - potentially leading to tunable exotic quantum transport. Here, we present magnetotransport measurements of a high-quality bilayer graphene-hexagonal boron nitride (hBN) heterostructure. The zero-degree alignment generates a strong moir\'e superlattice potential for the electrons in BBG and the resulting Landau fan diagram of longitudinal and Hall resistance displays a Hofstadter butterfly pattern with a high level of detail. We demonstrate that the intricate relationship between valley and layer degrees of freedom controls the topology of moir\'e-induced bands, significantly influencing the energetics of interacting quantum phases in the BBG superlattice. We further observe signatures of field-induced correlated insulators, helical edge states and clear quantizations of interaction-driven topological quantum phases, such as symmetry broken Chern insulators.

Author

Jeong, Yungi; Park, Hangyeol; Kim, Taeho; Watanabe, Kenji; Taniguchi, Takashi; Jung, Jeil; Jang, Joonho

Published

2023

Language

EN