Transport Equations and Spin-Charge Propagating Mode in the Two Dimensional Hole Gas

TL;DR

This paper demonstrates the existence of a propagating spin-charge mode with cubic dispersion in a strongly confined two-dimensional hole gas, revealing new dynamics beyond diffusive behavior due to spin-orbit coupling.

Contribution

It introduces a rigorous Keldysh approach to derive transport equations for 2DHG, uncovering a novel propagating mode of spin-charge motion.

Findings

Identification of a cubic dispersion propagating mode

Analysis of hole spin relaxation times and diffusion coefficients

Evidence that propagating modes are common in systems with spin-orbit coupling

Abstract

We find that the spin-charge motion in a strongly confined two-dimensional hole gas (2DHG) supports a propagating mode of cubic dispersion apart from the diffusive mode due to momentum scattering. Propagating modes seem to be a generic property of systems with spin-orbit coupling. Through a rigorous Keldysh approach, we obtain the transport equations for the 2DHG, we analyze the behavior of the hole spin relaxation time, the diffusion coefficients, and the spin-charge coupled motion.