Non-Drude Optical Conductivity of (III,Mn)V Ferromagnetic Semiconductors

TL;DR

This paper models the infrared optical properties of (III,Mn)V ferromagnetic semiconductors at zero temperature, highlighting the effects of disorder and interactions on their non-Drude conductivity and comparing findings with experimental data.

Contribution

It introduces a numerical model that simultaneously accounts for disorder and interactions, revealing non-Drude behavior and shifting oscillator weight in these semiconductors.

Findings

Absence of a clear Drude peak in conductivity

Broadened inter-band peak near 220 meV

Disorder shifts oscillator weight to higher frequencies

Abstract

We present a numerical model study of the zero-temperature infrared optical properties of (III,Mn)V diluted magnetic semiconductors. Our calculations demonstrate the importance of treating disorder and interaction effects simultaneously in modelling these materials. We find that the conductivity has no clear Drude peak, that it has a broadened inter-band peak near 220 meV, and that oscillator weight is shifted to higher frequencies by stronger disorder. These results are in good qualitative agreement with recent thin film absorption measurements. We use our numerical findings to discuss the use of f-sum rules evaluated by integrating optical absorption data for accurate carrier-density estimates.