Tuning of the Rashba effect in Pb quantum well states via a variable Schottky barrier

TL;DR

This paper demonstrates how the Rashba effect in Pb quantum well states can be tuned via the Schottky barrier doping, enabling potential applications in terahertz spin-FETs by controlling spin precession.

Contribution

It introduces a method to tune the Rashba spin splitting in Pb quantum well states through Schottky barrier doping, advancing spintronic device control.

Findings

Rashba effect in Pb quantum wells can be modulated by Schottky barrier doping.

Tuning the Rashba effect affects the spin precession angle.

Potential for terahertz spin-FET applications.

Abstract

Spin-orbit interaction (SOI) in low-dimensional systems results in the fascinating property of spin-momentum locking. In a Rashba system the inversion symmetry normal to the plane of a two-dimensional (2D) electron gas is broken, generating a Fermi surface spin texture reminiscent of spin vortices of different radii. This can be exploited in a spin-based field-effect transistor (spin- FET), where the Rashba system forms a 2D channel between ferromagnetic (FM) source and drain electrodes. The electron spin precesses when propagating through the Rashba channel and spin orientations (anti)parallel to the drain give (low) high conductivity. Crucial is the possibility to tune the momentum splitting, and consequently the precession angle, through an external parameter. Here we show that this can be achieved in Pb quantum well states through the doping dependence of the Schottky barrier, opening up the possibility of a terahertz spin-FET.