Resonant photovoltaic effect in doped magnetic semiconductors

TL;DR

This paper introduces the resonant photovoltaic effect (RPE), a second-order rectified response in doped magnetic semiconductors caused by anomalous velocities, producing a resonant current at the interband absorption threshold.

Contribution

It identifies and models the RPE, a novel second-order rectified response due to broken Kramers degeneracy and anomalous velocities in doped magnetic semiconductors.

Findings

RPE produces a resonant galvanic current peak at the interband absorption threshold.

The effect is demonstrated in a model of magnetized topological insulator surface states.

RPE is distinct from the intrinsic shift current in undoped semiconductors.

Abstract

The rectified non-linear response of a clean undoped semiconductor to an AC electric field includes a well known intrinsic contribution -- the shift current. We show that when Kramers degeneracy is broken, a distinct second order rectified response appears that is due to Bloch state anomalous velocities in a system with an oscillating Fermi surface. This effect, which we refer to as the resonant photovoltaic effect (RPE), produces a resonant galvanic current peak at the interband absorption threshold in doped semiconductors or semimetals with approximate particle-hole symmetry. We evaluate the RPE for a model of the surface states of a magnetized topological insulator.