Longitudinal spin decoherence in spin diffusion in semiconductors

TL;DR

This paper develops a many-body kinetic model to study spin transport in semiconductors, revealing a new inhomogeneous broadening effect that causes spin decoherence independently of scattering, challenging prior models.

Contribution

It introduces a revised kinetic framework and identifies a novel decoherence mechanism due to inhomogeneous broadening in spin diffusion.

Findings

Inhomogeneous broadening causes significant spin decoherence.

The decoherence effect can occur without scattering.

This effect surpasses traditional D'yakonov-Perel' dephasing.

Abstract

We have set up a set of many-body kinetic Bloch equations with spacial inhomogeneity. We reexamined the widely adopted quasi-independent electron model and showed the inadequacy of this model in studying the spin transport. We further pointed out a new decoherence effect based on interference effect along the diffusion in spin transport problem due to the so called inhomogeneous broadening effect in the Bloch equations. We have shown that this inhomogeneous broadening effect can cause the spin decoherence alone even without the scattering and that the resulting decoherence is more important than the dephasing effect due to the D'yakonov-Perel' (DP) term together with the scatterings.