Stacking-dependent Rashba spin-splitting in Janus bilayer transition metal dichalcogenides: The role of in-plane strain and out-of-plane electric field

Abstract

In this paper, we have applied first-principles calculations to investigate the structural, electronic and spintronic properties of the two-dimensional (2D) Janus bilayer transition metal dichalcogenides (TMDs) (MXY; M = Mo, W; X, YS, Se, Te). In Janus bilayer TMDs breaking out-of-plane symmetry causes intrinsic electric field which induces Rashba spin-splitting at the Γ-point in valence band and Zeeman-type spin-splitting at the K-point of both valence band and conduction band. Fifteen different stacking patterns of MoSeTe as an example have been investigated to find the most stable structures and the stacking configurations with Rashba spin-splitting. We have manipulated these spin properties by applying an external electric field parallel to the internal electric field to enhance the strength of it. Furthermore, we have explored the effect of in-plane biaxial strain on the electrical and spin properties of structures. Applying strain can significantly change and control the value of Rashba spin-splitting by modifying the orbitals overlap which can adjust the intrinsic electric field. Finally, our results are helpful in understanding the stacking-dependent Rashba spin-splitting in bilayer Janus transition-metal dichalcogenides and promote the application of bilayer MXY in spintronic applications.