Magneto-Gyrotropic Photogalvanic Effect in Semiconductor Quantum Wells

TL;DR

This paper explores the magneto-gyrotropic photogalvanic effect in semiconductor quantum wells, demonstrating how in-plane magnetic fields induce photocurrents under terahertz excitation, with effects separable in specific geometries.

Contribution

It provides both experimental and theoretical analysis of the magneto-gyrotropic photogalvanic effect in zinc-blende quantum wells, highlighting conditions for effect separation.

Findings

Magnetic field induces photocurrents at normal incidence.

Spin-galvanic and magneto-gyrotropic effects can be separated.

Photocurrents depend on excitation polarization and geometry.

Abstract

We investigate both experimentally and theoretically, the magneto-gyrotropic photogalvanic effect in zinc-blende based quantum wells with $C_{2v}$ point-group symmetry using optical excitation in the terahertz frequency range. The investigated frequencies cause intra-subband but no inter-band and inter-subband transitions. While at normal incidence the photocurrent vanishes at zero magnetic field, it is shown that an in-plane magnetic field generates photocurrents both for polarized and unpolarized excitation. In general the spin-galvanic effect, caused by circularly polarized light, and the magneto-gyrotropic effect, caused by unpolarized excitation, is superimposed. It is shown that in the case of two specific geometries both effects are separable.