Non-ohmic spin transport in n-type doped silicon

TL;DR

This paper demonstrates controlled spin-polarized electron transport in n-type silicon, showing how voltage tuning affects transport mechanisms and allows inference of long spin lifetimes despite short transit distances.

Contribution

It introduces a voltage-controlled method to manipulate spin transport mechanisms in silicon and models the process to infer long spin lifetimes from short transit times.

Findings

Voltage controls the dominant transport mechanism (drift vs. diffusion).

Monte-Carlo modeling matches experimental spin polarization data.

Transit time can be varied over 4 orders of magnitude.

Abstract

We demonstrate the injection and transport of spin-polarized electrons through n-type doped silicon with in-plane spin-valve and perpendicular magnetic field spin precession and dephasing ("Hanle effect") measurements. A voltage applied across the transport layer is used to vary the confinement potential caused by conduction band-bending and control the dominant transport mechanism between drift and diffusion. By modeling transport in this device with a Monte-Carlo scheme, we simulate the observed spin polarization and Hanle features, showing that the average transit time across the short Si transport layer can be controlled over 4 orders of magnitude with applied voltage. As a result, this modeling allows inference of a long electron spin lifetime, despite the short transit length.