Proximity-Induced\nExchange Interaction and Prolonged\nValley Lifetime in MoSe<sub>2</sub>/CrSBr Van-Der-Waals Heterostructure\nwith Orthogonal Spin Textures

Heterostructures, composed of semiconducting transition-metal\ndichalcogenides\n(TMDC) and magnetic van-der-Waals materials, offer exciting prospects\nfor the manipulation of the TMDC valley properties via proximity interaction\nwith the magnetic material. We show that the atomic proximity of monolayer\n MoSe<sub>2</sub> and the antiferromagnetic van-der-Waals crystal\nCrSBr leads to an unexpected breaking of time-reversal symmetry, with\noriginally perpendicular spin directions in both materials. The observed\neffect can be traced back to a proximity-induced exchange interaction\nvia first-principles calculations. The resulting spin splitting in\nMoSe<sub>2</sub> is determined experimentally and theoretically to\nbe on the order of a few meV. Moreover, we find a more than 2 orders\nof magnitude longer valley lifetime of spin-polarized charge carriers\nin 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\nheterostructure.