Magnetic and moir\'e Proximity Effects in WSe2/WSe2/CrI3 Trilayers

TL;DR

This paper investigates how magnetic and moiré proximity effects influence WSe2/WSe2/CrI3 trilayers, revealing tunable valley splitting, superlattice effects, and potential for novel topological states through first-principles calculations.

Contribution

It demonstrates the interplay of magnetic and moiré proximity effects in trilayers, showing how they can be engineered to produce enhanced valley splitting and topological states.

Findings

Large valley splitting due to super-exchange-like mechanism.

Electric-field tunability of valley splitting similar to Feshbach resonances.

Moiré superlattices amplify magnetic proximity effects.

Abstract

Integrating magnetic order to moir\'e superlattices is of significant scientific and technological interest. Based on first-principles calculations, we study the interplay of magnetic proximity and moir\'e proximity in WSe2/WSe2/CrI3 trilayers with different stackings and twist angles. Large valley splitting is observed due to redistribution of the exciton charge density across layers via a super-exchange-like mechanism, and its electric-field dependence bears similarity to electrically tunable and valley-selective Feshbach resonances. The valley splitting can be magnified in moir\'e superlattices owing to the superposition of Umklapp excitons folded from moir\'e minibands, yielding spatially modulated and enhanced magnetic proximity. The moir\'e proximity effect is demonstrated via an imprinted moir\'e potential on CrI3 layer and its feedback to the direct moir\'e potential on WSe2 bilayers is observed. The cooperation between the direct and imprinted moir\'e potentials is shown to yield novel topological and correlated states.