Spin dynamics in the strong spin-orbit coupling regime

TL;DR

This paper provides a comprehensive theoretical framework for understanding spin dynamics in high-mobility 2DEGs with strong spin-orbit interactions, revealing conditions for oscillatory modes and proposing new measurement techniques.

Contribution

It derives a full set of spin dynamic equations applicable from weak to strong SOI, capturing different spin evolution modes and linking them to experimental observables.

Findings

Damped oscillatory spin modes occur when scattering time exceeds half the spin precession time.

The theory aligns with recent experimental observations of spin dynamics.

A new method to measure scattering time and SOI strengths using optical grating experiments.

Abstract

We study the spin dynamics in a high-mobility two dimensional electron gas (2DEG) with generic spin-orbit interactions (SOIs). We derive a set of spin dynamic equations which capture the purely exponential to the damped oscillatory spin evolution modes observed in different regimes of SOI strength. Hence we provide a full treatment of the D'yakonov-Perel's mechanism by using the microscopic linear response theory from the weak to the strong SOI limit. We show that the damped oscillatory modes appear when the electron scattering time is larger than half of the spin precession time due to the SOI, in agreement with recent observations. We propose a new way to measure the scattering time and the relative strength of Rashba and linear Dresselhaus SOIs based on these modes and optical grating experiments. We discuss the physical interpretation of each of these modes in the context of Rabi oscillation.