Shot Noise Induced by Nonequilibrium Spin Accumulation

TL;DR

This paper reports the observation of excess shot noise caused by nonequilibrium spin accumulation in a semiconductor device, revealing a new way to study spin transport through noise measurements.

Contribution

It demonstrates that spin accumulation induces measurable shot noise proportional to the spin current, and quantifies the related electron temperature.

Findings

Excess shot noise is proportional to the spin current.

Spin accumulation affects electron temperature.

Shot noise measurement offers a new probe for spin transport.

Abstract

When an electric current passes across a potential barrier, the partition process of electrons at the barrier gives rise to the shot noise, reflecting the discrete nature of the electric charge. Here we report the observation of excess shot noise connected with a spin current which is induced by a nonequilibrium spin accumulation in an all-semiconductor lateral spin-valve device. We find that this excess shot noise is proportional to the spin current. Additionally, we determine quantitatively the spin-injection-induced electron temperature by measuring the current noise. Our experiments show that spin accumulation driven shot noise provides a novel means of investigating nonequilibrium spin transport.