Non-linear spin transport in a rectifying ferromagnet/semiconductor Schottky contact

TL;DR

This paper investigates how non-linear and rectifying electrical transport in ferromagnet/semiconductor Schottky contacts affects spin accumulation detection, revealing reduced sensitivity, increased back-flow, and potential for non-magnetic detection methods.

Contribution

It provides a theoretical analysis of non-linear spin transport in Schottky contacts, highlighting effects on spin detection sensitivity and the role of contact resistance.

Findings

Spin voltage expression matches linear case for small spin accumulation.

Non-linearity reduces spin detection sensitivity when spin accumulation is large.

Non-linearity allows non-magnetic metal contacts to detect spin accumulation.

Abstract

The electrical creation and detection of spin accumulation in ferromagnet/semiconductor Schottky contacts that exhibit highly non-linear and rectifying electrical transport is evaluated. If the spin accumulation in the semiconductor is small, the expression for the spin voltage is identical to that of linear transport. However, if the spin accumulation is comparable to the characteristic energy scale that governs the degree of non-linearity, the spin detection sensitivity and the spin voltage are notably reduced. Moreover, the non-linearity enhances the back-flow of spins into the ferromagnet and its detrimental effect on the injected spin current, and the contact resistance required to avoid back-flow is larger than for linear transport. It is also shown that by virtue of the non-linearity, a non-magnetic metal contact can be used to electrically detect spin accumulation in a semiconductor.