Orbital mechanism of the circular photogalvanic effect in quantum wells

TL;DR

This paper proposes an orbital mechanism for the circular photogalvanic effect in quantum wells, explaining how circularly polarized light induces a helicity-dependent photocurrent through interference effects, aligning with experimental data.

Contribution

It introduces a pure orbital mechanism based on interference of absorption pathways, providing a theoretical explanation for the observed photocurrent in quantum wells.

Findings

Photocurrent reverses with light helicity

Calculated photocurrent matches experimental observations

Mechanism is based on interference of absorption pathways

Abstract

It is shown that the free-carrier (Drude) absorption of circularly polarized radiation in quantum well structures leads to an electric current flow. The photocurrent reverses its direction upon switching the light helicity. A pure orbital mechanism of such a circular photogalvanic effect is proposed that is based on interference of different pathways contributing to the light absorption. Calculation shows that the magnitude of the helicity dependent photocurrent in $n$-doped quantum well structures corresponds to recent experimental observations.