Photogalvanic current in a double quantum well

TL;DR

This paper investigates the generation of a stationary in-plane photocurrent in a double quantum well system induced by linearly polarized light, highlighting the role of in-plane transition asymmetry and impurity scattering.

Contribution

It introduces a quantum mechanism for photocurrent generation involving indirect transitions and impurity scattering, with a focus on the resonant response to photon energy.

Findings

Photocurrent exhibits a resonant peak at photon energy matching subband separation.

The current is induced by linearly polarized light with both vertical and in-plane electric field components.

In-plane transition asymmetry due to impurity scattering is crucial for current generation.

Abstract

We study the in-plane stationary current caused by phototransitions between the states of a double quantum well. The electric polarization of light has both vertical and in-plane components. The stationary current originates from the periodic vibration of electrons between two non-equivalent quantum wells caused by the normal component of the alternating electric field with simultaneous in-plane acceleration/deceleration by the in-plane component of electric field. The quantum mechanism of the stationary current is conditioned by in-plane transition asymmetry which appears due to the indirect phototransitions with the participation of impurity scattering. The photocurrent has a resonant character corresponding to the equality of the photon energy to the distance between subbands. It is found that the current appears as a response to the linear-polarized light.