  Van der Waals (vdW) heterostructures composed of two-dimensional (2D)
transition metal dichalcogenides (TMD) and vdW magnetic materials offer an
intriguing platform to functionalize valley and excitonic properties in
non-magnetic TMDs. Here, we report magneto-photoluminescence (PL)
investigations of monolayer (ML) MoSe$_2$ on the layered A-type
antiferromagnetic (AFM) semiconductor CrSBr under different magnetic field
orientations. Our results reveal a clear influence of the CrSBr magnetic order
on the optical properties of MoSe$_2$, such as an anomalous linear-polarization
dependence, changes of the exciton/trion energies, a magnetic-field dependence
of the PL intensities, and a valley $g$-factor with signatures of an asymmetric
magnetic proximity interaction. Furthermore, first principles calculations
suggest that MoSe$_2$/CrSBr forms a broken-gap (type-III) band alignment,
facilitating charge transfer processes. The work establishes that
antiferromagnetic-nonmagnetic interfaces can be used to control the valley and
excitonic properties of TMDs, relevant for the development of opto-spintronics
devices.
