Monte Carlo modeling of spin injection through a Schottky barrier and spin transport in a semiconductor quantum well

TL;DR

This paper presents a Monte Carlo model for spin injection through a Schottky barrier into a semiconductor, analyzing spin dynamics influenced by spin-orbit interactions, and demonstrating substantial room-temperature spin polarization over micrometer scales.

Contribution

The study introduces a comprehensive Monte Carlo simulation incorporating thermionic and tunneling injection, along with advanced spin-orbit interactions, to analyze spin transport in semiconductor heterostructures.

Findings

Injected electrons maintain significant spin polarization over ~1 micrometer at room temperature.

The model accounts for non-thermalized electrons due to barrier shape.

Spin polarization persists without external magnetic fields.

Abstract

We develop a Monte Carlo model to study injection of spin-polarized electrons through a Schottky barrier from a ferromagnetic metal contact into a non-magnetic low-dimensional semiconductor structure. Both mechanisms of thermionic emission and tunneling injection are included in the model. Due to the barrier shape, the injected electrons are non-thermalized. Spin dynamics in the semiconductor heterostructure is controlled by the Rashba and Dresselhaus spin-orbit interactions and described by a single electron spin density matrix formalism. In addition to the linear term, the third order term in momentum for the Dresselhaus interaction is included. Effect of the Schottky potential on the spin dynamics in a 2 dimensional semiconductor device channel is studied. It is found that the injected current can maintain substantial spin polarization to a length scale in the order of 1 micrometer at room temperature without external magnetic fields.