Manipulation of Rashba spin splitting in 2D Janus WSeTe by strain and electric field: a first-principles study

A research hotspot in recent years has been regulating the Rashba spin splitting under low-power operation. This study focuses on WSeTe due to its intrinsic structural asymmetry and strong spin-orbit coupling (SOC). Herein, we have investigated the Rashba spin splitting in monolayer WSeTe based on first-principles density functional theory calculations. Our study reveals how strain-electric field manipulates the Rashba spin splitting, with strain playing a dominant role. Strain engineering can significantly enhance the Rashba spin splitting strength by regulating the orbital hybridization strength and the degree of orbital overlap, while external electric field manipulation is limited due to the geometric screening effect and polarization compensation. Strain plays a dominant role in Strain-electric field manipulation. Meanwhile, we found that a larger compressive strain (-3%) could modestly suppress the Rashba spin splitting, and such a suppressive effect can be mitigated by applying a vertical electric field. This confirms a synergetic effect of the strain-electric field on tuning the Rashba spin splitting. The strain-electric field manipulation of the Rashba spin splitting in the two-dimensional Janus structure provides new possibilities for the application of two-dimensional materials in spin electronics, quantum computing and other fields.