Spin waves in semiconductor microcavities

TL;DR

This paper theoretically demonstrates that spin-polarized exciton-polaritons in semiconductor microcavities can support propagating spin waves with dispersion characteristics influenced by interactions and spin anisotropy, affecting spin dynamics.

Contribution

It introduces a theoretical model describing spin wave propagation and dispersion in a gas of spin-polarized exciton-polaritons, highlighting the effects of spin-anisotropy.

Findings

Spin waves exhibit parabolic dispersion at small wavevectors.

Dispersion depends on polariton-polariton interaction constant.

Spin anisotropy influences the frequency of spin precession.

Abstract

We show theoretically that a weakly interacting gas of spin-polarized exciton-polaritons in a semiconductor microcavity supports propagation of spin waves. The spin waves are characterised by a parabolic dispersion at small wavevectors which is governed by the polariton-polariton interaction constant. Due to spin-anisotropy of polariton-polariton interactions the dispersion of spin waves depends on the orientation of the total polariton spin. For the same reason, the frequency of homogeneous spin precession/polariton spin resonance depends on their polarization degree.