Unidirectional magnetoresistance in the van der Waals antiferromagnet CrP S 4

As a typical nonlinear magnetoresistance, unidirectional magnetoresistance (UMR) has recently been observed in antiferromagnetic (AFM) systems with canted spin structure. However, a profound understanding of AFM UMR induced by interfacial spin-orbit coupling (SOC) is still lacking to date. In this paper, we choose van der Waals canted antiferromagnetic $\mathrm{CrP}{\mathrm{S}}_{4}$ due to the relatively low magnetic anisotropy and weak interlayer coupling, which enables a canted-AFM state between two adjacent layers under an in-plane magnetic field, and systematically investigate SOC-induced AFM UMR in $\mathrm{CrP}{\mathrm{S}}_{4}/\mathrm{Pt}$ heterostructure. We experimentally observe two characteristic UMR tendencies versus magnetic field in $\mathrm{CrP}{\mathrm{S}}_{4}/\mathrm{Pt}$ devices. The different UMR tendencies may be attributed to the interfacial defect-induced Fermi level change, which is supported by density-functional theory calculations and Boltzmann transport formalism. Our work provides a more profound understanding of the nontrivial AFM UMR and may facilitate the development of two-dimensional AFM spintronic devices.