Spin-orbit effects on the Larmor dispersion relation in GaAs quantum wells

TL;DR

This study investigates how spin-orbit coupling influences the Larmor resonance dispersion in GaAs quantum wells, revealing a magnetic field-dependent contribution to spin splitting from Dresselhaus and Rashba effects.

Contribution

It provides a detailed analysis of the spin-orbit interaction's role in Zeeman and spin-density excitations, especially at high magnetic fields, incorporating both Dresselhaus and Rashba terms.

Findings

Spin-orbit coupling couples Zeeman and spin-density excitations.

At high magnetic fields, spin-orbit yields a B-independent contribution to spin splitting.

In the small B limit, spin-orbit does not affect the spin splitting.

Abstract

We have studied the relevance of spin-orbit coupling to the dispersion 00009 relation of the Larmor resonance observed in inelastic light scattering and electron-spin resonance experiments on GaAs quantum wells. We show that the spin-orbit interaction, here described by a sum of Dresselhaus and Bychkov-Rashba terms, couples Zeeman and spin-density excitations. We have evaluated its contribution to the spin splitting as a function of the magnetic field $B$, and have found that in the small $B$ limit, the spin-orbit interaction does not contribute to the spin splitting, whereas at high magnetic fields it yields a $B$ independent contribution to the spin splitting given by $2(\lambda_R^2-\lambda_D^2)$, with $\lambda_{R,D}$ being the intensity of the Bychkov-Rashba and Dresselhaus spin-orbit terms.