Spin Splitting Induced Photogalvanic Effect in Quantum Wells

TL;DR

This paper develops a theoretical model for the circular photogalvanic effect in quantum wells, showing how spin splitting influences photocurrent spectra depending on the type of spin-orbit interaction.

Contribution

It provides a novel theoretical framework linking spin splitting types to photocurrent spectra in quantum wells, highlighting the effects of Rashba and Dresselhaus interactions.

Findings

Photocurrent spectrum depends on spin-orbit interaction form.

Rashba splitting causes a linear frequency dependence near the absorption edge.

Dresselhaus splitting results in a parabolic edge behavior.

Abstract

A theory of the circular photogalvanic effect caused by spin splitting in quantum wells is developed. Direct interband transitions between the hole and electron size-quantized subbands are considered. The photocurrent excitation spectrum is shown to depend strongly on the form of the spin-orbit interaction. In the case of structure inversion asymmetry induced (Rashba) spin-splitting, the current is a linear function of light frequency near the absorption edge, and for the higher excitation energy the spectrum changes its sign and has a minimum. In contrast, when the bulk inversion asymmetry (Dresselhaus splitting) dominates, the photocurrent edge behavior is parabolic, and then the spectrum is sign-constant and has a maximum.