Dynamic spin injection into a quantum well coupled to a spin-split bound state

TL;DR

This paper provides a theoretical analysis of how Coulomb correlations influence dynamic spin injection and polarization in a quantum well coupled to a spin-split bound state, revealing controllable effects for experimental study.

Contribution

It introduces a theoretical framework that accounts for Coulomb interactions in spin-dependent tunneling, highlighting their role in enhancing spin polarization and delaying tunneling in quantum wells.

Findings

Coulomb repulsion enhances dynamic spin polarization.

Delay in carrier tunneling due to Coulomb interactions.

Controllable effects via relaxation rate adjustments.

Abstract

We present a theoretical analysis of dynamic spin injection due to spin-dependent tunneling between a quantum well (QW) and a bound state split in spin projection due to an exchange interaction or external magnetic field. We focus on the impact of Coulomb correlations at the bound state on spin polarization and sheet density kinetics of the charge carriers in the QW. The theoretical approach is based on kinetic equations for the electron occupation numbers taking into account high order correlation functions for the bound state electrons. It is shown that the on-site Coulomb repulsion leads to an enhanced dynamic spin polarization of the electrons in the QW and a delay in the carriers tunneling into the bound state. The interplay of these two effects leads to non-trivial dependence of the spin polarization degree, which can be probed experimentally using time-resolved photoluminescence experiments. It is demonstrated that the influence of the Coulomb interactions can be controlled by adjusting the relaxation rates. These findings open a new way of studying the Hubbard-like electron interactions experimentally.