Infrared magneto-optical properties of (III,Mn)V ferromagetic semiconductors

TL;DR

This paper provides a theoretical analysis of the infrared magneto-optical properties of (III,Mn)V ferromagnetic semiconductors, predicting features in ac-Hall conductivity and effects like Kerr rotation based on band transitions and disorder effects.

Contribution

It combines a kinetic exchange model with linear response theory to predict magneto-optical features and connect them with experimental observations in (III,Mn)V semiconductors.

Findings

Predicted a prominent ac-Hall conductivity feature at 200-400 meV.

Reduced Hall conductivity to the Berry's phase in the zero-frequency limit.

Estimated magneto-optical effects like Kerr rotation and Faraday rotation as functions of material parameters.

Abstract

We present a theoretical study of the infrared magneto-optical properties of ferromagnetic (III,Mn)V semiconductors. Our analysis combines the kinetic exchange model for (III,Mn)V ferromagnetism with Kubo linear response theory and Born approximation estimates for the effect of disorder on the valence band quasiparticles. We predict a prominent feature in the ac-Hall conductivity at a frequency that varies over the range from 200 to 400 meV, depending on Mn and carrier densities, and is associated with transitions between heavy-hole and light-hole bands. In its zero frequency limit, our Hall conductivity reduces to the $\vec k$-space Berry's phase value predicted by a recent theory of the anomalous Hall effect that is able to account quantitatively for experiment. We compute theoretical estimates for magnetic circular dichroism, Faraday rotation, and Kerr effect parameters as a function of Mn concentration and free carrier density. The mid-infrared response feature is present in each of these magneto-optical effects.