Adjustable Electronic Properties of Two-Dimensional Ferromagnetic Semiconductor CrSBr by van der Waals Interfacial Coupling

Two-dimensional (2D) ferromagnetic semiconductors have attracted much attention due to their broad application prospects in future spintronic devices. The CrSBr monolayer fabricated from a recent experiment is a particularly promising ferromagnetic semiconductor with favorable air stability and moderate band gap. Nevertheless, its practical use is limited by Curie temperatures (T-C) below room temperature. Herein, the CrSBr/BP van der Waals (vdW) heterostructure is constructed to explore improvement of electronic and magnetic properties. First-principles calculations show that although the vdW interfacial coupling provides an additional superexchange path (Cr-P-Cr) for the ferromagnetic coupling of the CrSBr layer in the heterostructure, the ferromagnetism of the heterostructure is weakened by a smaller a-axis lattice constant. The tensile strain along the a-axis will enhance the ferromagnetic coupling of the heterostructure, and the T-C increases to 198 K when the strain is 5%. The semiconductor characteristics and easy magnetization direction of the heterostructure are well preserved. Moreover, the smaller hole effective mass of the heterostructure at the Gamma point makes its hole mobility reach 3589 cm(2) V-1 S- 1. The findings in this work provide new strategies for improving the ferromagnetic stability of 2D semiconductors and further promote the relevant theoretical and experimental research.