Rashba spin-splitting in Janus SnXY/WXY (X, Y = S, Se, Te; X ≠ Y) heterostructures.

Abstract

Janus transition metal dichalcogenide monolayers have shown a lack of mirror symmetry perpendicular to the 2D plane. The breaking of out-of-plane symmetry, along with the spin-orbit coupling, induces Rashba spin-splitting in these materials. In this work, Rashba spin splitting in Janus tin dichalcogenide monolayers are studied. In addition, the heterostructures of Janus SnXY and WXY (X, Y = S, Se, Te; X 6 = Y) monolayers are discussed. A Rashba spin-splitting energy of about 43 meV, more significant than the room temperature energy, is observed in the Janus SnSSe/WSSe heterostructure. The consequences of vertical strain on the semiconducting heterostructure are examined. Compressive vertical strain enhances the Rashba splitting, and tensile strain reduces the spin-splitting. For the compressive strain of 10.4%, Janus SnSSe/WSSe heterostructure remains semiconductor with only Rashba bands surrounding near the Fermi level. Enhanced Rashba parameter of about 0.96 eVÅ and splitting energy of about 72 meV are observed. These findings confirm that Janus SnSSe/WSSe heterostructure is a productive Rashba material for spintronic device applications.