Magneto-electric photocurrent generated by direct inter-band transitions in InGaAs/InAlAs two-dimensional electron gas

TL;DR

This study demonstrates the generation of magneto-electric photocurrent in an InGaAs/InAlAs 2D electron gas via direct inter-band transitions, revealing polarization dependence and spin photocurrent conversion efficiency.

Contribution

It provides the first microscopic explanation of polarization-dependent magneto-electric photocurrent in this material system, linking spin photocurrent to electric current.

Findings

Electric current proportional to in-plane magnetic field.

Polarization dependence explained microscopically.

Conversion coefficient of spin photocurrent estimated.

Abstract

We report observation of magneto-electric photocurrent generated via direct inter-band transitions in an InGaAs/InAlAs two-dimensional electron gas excited by a linearly polarized incident light.The electric current is proportional to the in-plane magnetic field which unbalances the velocities of the photoexcited carriers with opposite spins and consequently generates electric current from a spin photocurrent. The observed light polarization dependence of the electric current is explained microscopically by taking into account of the anisotropy of the photoexcited carrier density in wave vector space. The spin photocurrent can be extracted from the measured current and the conversion coefficient of spin photocurrent to electric current is estimated to be $10^{-3}$$\sim$$10^{-2}$ per Tesla.