Zero field spin splitting in AlSb/InAs/AlSb quantum wells induced by surface proximity effects

TL;DR

This study demonstrates zero-field spin splitting in shallow AlSb/InAs/AlSb quantum wells caused by surface proximity effects, with implications for mesoscopic device applications relying on surface-sensitive spin properties.

Contribution

It reveals that surface proximity induces significant Rashba spin splitting in shallow quantum wells, a novel insight into surface-induced spin phenomena in semiconductor heterostructures.

Findings

Spin splitting energies exceed 2.3 meV at zero magnetic field

Surface proximity causes band bending leading to Rashba effect

Electron transfer from surface to quantum well is significant

Abstract

InAs quantum well heterostructures are of considerable interest for mesoscopic device applications such as scanning probe and magnetic recording sensors, which require the channel to be close to the surface. Here we report on magnetotransport measurements of AlSb/InAs/AlSb Hall bars at a shallow depth of 20 nm. Analysis of the observed Shubnikov-de Haas oscillations and modeling show that spin splitting energies in excess of 2.3 meV occur at zero magnetic field. We conclude that the spin-splitting results from the Rashba effect due to the band bending in the quantum well. This is caused by substantial electron transfer from the surface to the quantum well and becomes significant when the quantum well is located near the surface.