Electrical control of valley-Zeeman spin-orbit coupling-induced spin precession at room temperature

TL;DR

This paper demonstrates room-temperature electrical control of spin precession in bilayer graphene via proximity-induced spin-orbit coupling, enabling a spin field-effect transistor with potential for energy-efficient spintronics.

Contribution

It introduces a method to manipulate spin precession electrically in 2D materials at room temperature, a significant step forward for spintronic device development.

Findings

Coherent spin precession achieved without external magnetic field.

Precession sign tunable by back gate voltage and drift current.

Realization of a spin field-effect transistor at room temperature.

Abstract

The ultimate goal of spintronics is achieving electrically controlled coherent manipulation of the electron spin at room temperature to enable devices such as spin field-effect transistors. With conventional materials, coherent spin precession has been observed in the ballistic regime and at low temperatures only. However, the strong spin anisotropy and the valley character of the electronic states in 2D materials provide unique control knobs to manipulate spin precession. Here, by manipulating the anisotropic spin-orbit coupling in bilayer graphene by the proximity effect to WSe$_2$, we achieve coherent spin precession in the absence of an external magnetic field, even in the diffusive regime. Remarkably, the sign of the precessing spin polarization can be tuned by a back gate voltage and by a drift current. Our realization of a spin field-effect transistor at room temperature is a cornerstone for the implementation of energy-efficient spin-based logic.