Large quantum anomalous Hall effect in spin-orbit proximitized rhombohedral graphene.

Han, Tonghang; Lu, Zhengguang; Yao, Yuxuan; Yang, Jixiang; Seo, Junseok; Yoon, Chiho; Watanabe, Kenji; Taniguchi, Takashi et al. · Science · 2024

basic_science · Level V

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Abstract

The quantum anomalous Hall effect (QAHE) is a robust topological phenomenon that features quantized Hall resistance at zero magnetic field. We report the QAHE in a rhombohedral pentalayer graphene-monolayer tungsten disulfide (WS<sub>2</sub>) heterostructure. Distinct from other experimentally confirmed QAHE systems, this system has neither magnetic element nor moiré superlattice effect. The QAH states emerge at charge neutrality and feature Chern numbers <i>C</i> = ±5 at temperatures of up to about 1.5 kelvin. This large QAHE arises from the synergy of the electron correlation in intrinsic flat bands of pentalayer graphene, the gate-tuning effect, and the proximity-induced Ising spin-orbit coupling. Our experiment demonstrates the potential of crystalline two-dimensional materials for intertwined electron correlation and band topology physics and may enable a route for engineering chiral Majorana edge states.