Experimental Separation of Rashba and Dresselhaus Spin-Splittings in Semiconductor Quantum Wells

TL;DR

This paper presents a novel experimental method to directly measure and distinguish the Rashba and Dresselhaus spin-orbit coupling strengths in semiconductor quantum wells using photocurrent measurements and spin-galvanic effect angular distributions.

Contribution

It introduces a new experimental technique that directly extracts the ratio of Rashba and Dresselhaus coefficients without relying on theoretical models.

Findings

Successfully measured Rashba and Dresselhaus contributions in InAs quantum wells.

Demonstrated the technique's ability to determine spin-orbit coupling ratios directly from experiments.

Opened a new pathway for analyzing spin-orbit effects in semiconductor structures.

Abstract

The relative strengths of Rashba and Dresselhaus terms describing the spin-orbit coupling in semiconductor quantum well (QW) structures are extracted from photocurrent measurements on n-type InAs QWs containing a two-dimensional electron gas (2DEG). This novel technique makes use of the angular distribution of the spin-galvanic effect at certain directions of spin orientation in the plane of a QW. The ratio of the relevant Rashba and Dresselhaus coefficients can be deduced directly from experiment and does not relay on theoretically obtained quantities. Thus our experiments open a new way to determine the different contributions to spin-orbit coupling.