Efficient switching of Rashba spin splitting in wide modulation-doped quantum wells

TL;DR

This paper shows how the Rashba spin splitting in wide modulation-doped quantum wells can be efficiently controlled by electric field variation, leading to significant changes in spin properties and potential spintronic applications.

Contribution

It reveals that the Rashba spin splitting can be strongly modulated by electric field asymmetry in wide quantum wells, a novel control mechanism.

Findings

Rashba spin splitting varies significantly with electric field asymmetry.

Asymmetry can enhance Rashba splitting by an order of magnitude.

Spin wave functions and directions can be completely altered by in-plane wave vector changes.

Abstract

We demonstrate that the size of the electric-field-induced Rashba spin splitting in an 80 nm wide modulation-doped InGaSb quantum well can depend strongly on the spatial variation of the electric field. In a slightly asymmetric quantum well it can be an order of magnitude stronger than for the average uniform electric field. For even smaller asymmetry spin subbands can have wave functions and/or expectation values of the spin direction that are completely changed as the in-plane wave vector varies. The Dresselhaus effect can give an anticrossing at which the spin rapidly flips.