Nonvolatile tuning of the Rashba effect in the CuInP2S6/MoSSe/CuInP2S6 heterostructure

Abstract

The van der Waals sandwich heterostructure CuInP2S6/MoSSe/CuInP2S6 (CIPS/MoSSe/CIPS) has first been employed as a prototype to tune the Rashba effect. By nonvolatile controlling of the orientation of the polarization of the top ferroelectric CIPS monolayer, it is confirmed that the Rashba effect can be switched on or off at the top position of the valence band (VB) around the Γ point. More significantly, we find that the Rashba coefficient increases by almost one order of magnitude for the “on” state as compared with the freestanding MoSSe monolayer. Based on the results of first-principle calculations, it is obtained that the enhancement of the Rashba effect results from the charge transfer from the top CIPS layer to the MoSSe layer or the bottom CIPS layer, and the lifting of the d-orbit band of the light Cu atom leads to the disappearance of Rashba spin splitting at the top of the VB around the Γ point. Furthermore, the polarization orientation of the bottom CIPS layer can greatly alter the bandgap of the sandwich structure. We hope the above nonvolatile and large amplitude tuning of the Rashba effect should be useful in the design of spintronic nano-devices.