Observation of electric current induced by optically injected spin current

TL;DR

This paper reports the experimental detection of an electric current generated by optically injected spin currents in a semiconductor quantum well, demonstrating a new method for studying spin phenomena.

Contribution

It presents the first observation of an electric current induced by optically injected spin currents in a 2D electron gas, linking spin injection to measurable charge currents.

Findings

Electric current exhibits a butterfly-like pattern.

Current depends on light polarization similarly to spin current.

Provides a new technique for detecting spin currents.

Abstract

A normally incident light of linear polarization injects a pure spin current in a strip of 2-dimensional electron gas with spin-orbit coupling. We report observation of an electric current with a butterfly-like pattern induced by such a light shed on the vicinity of a crossbar shaped InGaAs/InAlAs quantum well. Its light polarization dependence is the same as that of the spin current. We attribute the observed electric current to be converted from the optically injected spin current caused by scatterings near the crossing. Our observation provides a realistic technique to detect spin currents, and opens a new route to study the spin-related science and engineering in semiconductors.