Out-of-plane carrier spin in transition-metal dichalcogenides under electric current

TL;DR

This paper proposes that out-of-plane carrier spin can be generated in ferromagnetic transition-metal dichalcogenide monolayers due to intrinsic spin-orbit coupling, enabling electric control of spin and valley polarization.

Contribution

It introduces a novel mechanism for out-of-plane spin generation in monolayer TMDs, supported by symmetry analysis and first-principles calculations.

Findings

Out-of-plane spin can be induced in ferromagnetic TMD monolayers.

Current direction influences the induced spin and valley polarization.

The mechanism enables electric control of magnetization and valley states.

Abstract

In a multilayer comprising ferromagnet and heavy metal, in-plane carrier spin is induced by applied electric current owing to Rashba spin-orbit coupling, while the out-of-plane component is absent. We propose the out-of-plane carrier spin can emerge in ferromagnetic transition-metal dichalcogenides monolayer, by symmetry arguments and first-principles calculations. An intrinsic spin-orbit coupling in the monolayer provides valley-contrasting Zeeman-type spin splitting for generating the vertical induced spin. The current direction can be exploited to tune the induced spin, accompanied with valley polarization. The exotic spin accumulation paves an accessible way for perpendicular magnetization switching and electric control of valleys.