Strain-induced and charge doping manipulation of the Rashba spin splitting in Janus van der Waals PtSeTe/Se2Te heterostructures

Abstract

The out-of-plane mirror-symmetry breaking in Janus transition metal dichalcogenides(J-TMDs) and their van der Waals heterostructures (vdW HSs) induces intrinsic Rashba splitting, which could offer the possibility to revolutionize spintronic devices. However, there is some controversy about the fundamental reason of Rashba splitting changes under different manipulation methods. This study investigates the Rashba splitting in AA-stacking Janus PtSeTe/Se₂Te vdW HS with a Te − Te interface by first-principles calculations, as well as the manipulation of Rashba splitting through charge doping and in-plane biaxial strain. The interlayer distance exhibits an inverse relationship with biaxial strain, while the potential profile of the HS remains almost same. Consequently, it can be inferred that the intrinsic electric field is influenced by the interlayer distance under biaxial strain. Thus, the underlying physical mechanism responsible for the changes in Rashba splitting due to biaxial strain is attributed to the variation in interlayer distance. The Rashba splitting shows a linear variation within the charge doping range of −0.5e to 0.3e, while it demonstrates a nonlinear variation in the range of 0.3e to 0.5e, which may be related to the electronegativity reversal of the PtSeTe layer at 0.3e charge doping. These results enrich the fundamental understanding of the Rashba effect in Janus HS.