Circular and Linear Photogalvanic Effects in Type-II GaSb/InAs Quantum Well Structures in the Inverted Regime

TL;DR

This study observes and analyzes circular and linear photogalvanic effects induced by terahertz radiation in type-II GaSb/InAs quantum wells with inverted band structure, combining experimental results with a microscopic theoretical model.

Contribution

It provides the first detailed experimental and theoretical investigation of photogalvanic effects in type-II GaSb/InAs quantum wells with inverted band order.

Findings

Photocurrents are induced at oblique incidence by terahertz radiation.

Both circular and linear photogalvanic effects are significant.

Theoretical model agrees well with experimental data.

Abstract

We report on the observation of photogalvanic effects induced by terahertz radiation in type-II GaSb/InAs quantum wells with inverted band order. Photocurrents are excited at oblique incidence of radiation and consists of several contributions varying differently with the change of the radiation polarization state; the one driven by the helicity and the other one driven by the linearly polarization of radiation are of comparable magnitudes. Experimental and theoretical analyses reveal that the photocurrent is dominated by the circular and linear photogalvanic effects in a system with a dominant structure inversion asymmetry. A microscopic theory developed in the framework of the Boltzmann equation of motion considers both photogalvanic effects and describes well all the experimental findings.