Remanent anomalous Hall effect from dual spin-orbit and exchange proximity in graphene heterostructure

Résumé :

The coexistence of induced spin-orbit coupling (SOC) and magnetic exchange fields is predicted to drive graphene into topological phases, such as the quantum anomalous Hall state. In this talk, I will discuss the prospect of using monolayer graphene proximitized by WSe2 (SOC) and Cr2Ge2Te6 (magnetic exchange) to reach such “ex-so-tic” states. Low-temperature magnetotransport measurements of the heterostructures reveal a large and gate-tunable remanent anomalous Hall effect (AHE) persisting at zero magnetic field. Combining data analysis over various magnetic field ranges and a simple model, we explain our findings by an intrinsic AHE regime, where Berry curvature hot-spots from the interplay of SOC and magnetism dominate the Hall response, but disorder broadening prevents quantization and a full topological phase transition. These results demonstrate the potential of double proximity effects in graphene-based van der Waals heterostructures as a route toward gate-tunable topological graphene phases and devices based on chiral edge states.

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Contact : florence.levy-bertrand@neel.cnrs.fr