Proximity-Induced Exchange Interaction and Prolonged Valley Lifetime in MoSe<sub>2</sub>/CrSBr Van-Der-Waals Heterostructure with Orthogonal Spin Textures.

Beer, Andreas; Zollner, Klaus; Serati de Brito, Caique; Faria Junior, Paulo E; Parzefall, Philipp; Ghiasi, Talieh S; Ingla-Aynés, Josep; Mañas-Valero, Samuel et al. · ACS Nano · 2024

basic_science · Level V

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Abstract

Heterostructures, composed of semiconducting transition-metal dichalcogenides (TMDC) and magnetic van-der-Waals materials, offer exciting prospects for the manipulation of the TMDC valley properties via proximity interaction with the magnetic material. We show that the atomic proximity of monolayer MoSe<sub>2</sub> and the antiferromagnetic van-der-Waals crystal CrSBr leads to an unexpected breaking of time-reversal symmetry, with originally perpendicular spin directions in both materials. The observed effect can be traced back to a proximity-induced exchange interaction via first-principles calculations. The resulting spin splitting in MoSe<sub>2</sub> is determined experimentally and theoretically to be on the order of a few meV. Moreover, we find a more than 2 orders of magnitude longer valley lifetime of spin-polarized charge carriers in the heterostructure, as compared to monolayer MoSe<sub>2</sub>/SiO<sub>2</sub>, driven by a Mott transition in the type-III band-aligned heterostructure.