Rashba and Dresselhaus Spin-Splittings in Semiconductor Quantum Wells Measured by Spin Photocurrents

TL;DR

This paper uses spin photocurrents induced by terahertz radiation to measure and compare Rashba and Dresselhaus spin-splittings in semiconductor quantum wells, providing insights for spintronic device design.

Contribution

It introduces a method to determine the relative strengths of Rashba and Dresselhaus effects in quantum wells using spin photocurrents, highlighting how doping position affects spin-splitting signs.

Findings

Shifting doping plane changes Rashba photocurrent sign

Dresselhaus photocurrent sign remains unchanged

Method aids in designing structures with balanced or zero Rashba splitting

Abstract

The spin-galvanic effect and the circular photogalvanic effect induced by terahertz radiation are applied to determine the relative strengths of Rashba and Dresselhaus band spin-splitting in (001)-grown GaAs and InAs based two dimensional electron systems. We observed that shifting the $\delta$-doping plane from one side of the quantum well to the other results in a change of sign of the photocurrent caused by Rashba spin-splitting while the sign of the Dresselhaus term induced photocurrent remains. The measurements give the necessary feedback for technologists looking for structures with equal Rashba and Dresselhaus spin-splittings or perfectly symmetric structures with zero Rashba constant.