Electric field control of spin-orbit splittings in GaAs/AlGaAs coupled quantum wells

TL;DR

This study demonstrates that applying an electrical bias to GaAs/AlGaAs coupled quantum wells allows control over spin-orbit splittings and electron spin dephasing anisotropy, with potential implications for spintronic devices.

Contribution

It provides experimental and theoretical insights into electrical control of spin-orbit interactions in coupled quantum wells, highlighting the tunability of spin dephasing anisotropy.

Findings

Spin dephasing time anisotropy is controllable by electrical bias.

The ratio of Rashba to Dresselhaus spin splittings varies with bias.

Electrical bias influences spin-orbit coupling in quantum wells.

Abstract

Electron spin dynamics is investigated in n-i-n GaAs/AlGaAs coupled quantum wells. The electron spin dephasing time is measured as a function of an external electrical bias under resonant excitation of the 1sHH intrawell exciton using a time-resolved Kerr rotation technique. It is found a strong electron spin dephasing time anisotropy caused by an interference of the structure inversion asymmetry and the bulk inversion asymmetry. This anisotropy is shown to be controlled by an electrical bias. A theoretical analysis of electron spin dephasing time anisotropy is developed. The ratio of Rashba and Dresselhaus spin splittings is studied as a function of applied bias.