Microscopic analysis of the coherent optical generation and the decay of charge and spin currents in semiconductor heterostructures

TL;DR

This paper provides a microscopic analysis of how coherent optical methods generate and decay charge and spin currents in semiconductor heterostructures, considering complex many-body effects and predicting nonmonotonous current behaviors.

Contribution

It introduces a detailed microscopic model including excitonic effects, scattering processes, and nonperturbative excitations, revealing new insights into current dynamics and damping mechanisms.

Findings

Currents depend nonmonotonously on laser intensity.

Spin current damping exceeds charge current damping due to Coulomb scattering.

Microscopic effects significantly influence current generation and decay in heterostructures.

Abstract

The coherent optical injection and temporal decay of spin and charge currents in semiconductor heterostructures is described microscopically, including excitonic effects, carrier LO-phonon and carrier-carrier scattering, as well as nonperturbative light-field-induced intraband and interband excitations. A nonmonotonous dependence of the currents on the intensities of the laser beams is predicted. Enhanced damping of the spin current relative to the charge current is obtained as a consequence of spin-dependent Coulomb scattering.