Direct detection of the relative strength of Rashba and Dresselhaus spin-orbit interaction: Utilizing the SU(2) symmetry

TL;DR

This paper introduces a straightforward method to measure the relative strengths of Rashba and Dresselhaus spin-orbit interactions in quantum wells by analyzing asymmetries in critical gate voltages linked to SU(2) symmetry, supported by numerical simulations.

Contribution

The paper presents a novel, gate-voltage-based approach to determine the ratio of Rashba and Dresselhaus spin-orbit coupling strengths without directional dependence, applicable to various nanostructures.

Findings

Critical gate voltages reveal SU(2) symmetry points.

Maximum spin relaxation times indicate spin-orbit ratio.

Method validated through numerical calculations.

Abstract

We propose a simple method to detect the relative strength of Rashba and Dresselhaus spin-obit interactions in quantum wells (QWs) without relying on the directional-dependent physical quantities. This method utilize the asymmetry of critical gate voltages that leading to the remarkable signals of SU(2) symmetry, which happens to reflect the intrinsic structure inversion asymmetry of the QW. We support our proposal by the numerical calculation of in-plane relaxation times based on the self-consistent eight-band Kane model. We find that the two different critical gate voltages leading to the maximum spin relaxation times [one effect of the SU(2) symmetry] can simply determine the ratio of the coefficients of Rashba and Dresselhaus terms. Our proposal can also be generalized to extract the relative strengths of the spin-orbit interactions in quantum wire and quantum dot structures.