Spin-dependent phenomena in semiconductors in strong electric fields

TL;DR

This paper develops a theory for spin-dependent effects in semiconductors under strong electric fields, revealing significant modifications in spin relaxation, increased spin polarization, and oscillatory spin dynamics due to ballistic electron acceleration.

Contribution

It introduces a novel theoretical framework describing spin phenomena in the streaming regime, highlighting how ballistic acceleration alters spin relaxation and polarization behaviors.

Findings

Dyakonov-Perel spin relaxation is significantly modified

Current-induced spin orientation reaches ~2% at ~1kV/cm

Predicted oscillatory spin polarization dynamics in photocarriers

Abstract

We develop a theory of spin-dependent phenomena in the streaming regime characterized by ballistic acceleration of electrons in the moderate electric field until they achieve the optical phonon energy and abruptly emit the phonons. It is shown that the Dyakonov-Perel spin relaxation is drastically modified in this regime, the current-induced spin orientation remarkably increases, reaches a high value ~2% in the electric field ~1kV/cm and falls with the further increase in the field. The spin polarization enhancement is caused by squeezing of the electron momentum distribution in the direction of drift. We also predict field-induced oscillatory dynamics of spin polarization of the photocarriers excited into the conduction band by a short circularly-polarized optical pulse.