Disorder-Induced Effects in III-V Semiconductors with Mn

TL;DR

This paper investigates how Mn doping and compensating donors alter the electronic band structure and optical absorption in III-V semiconductors, combining ab initio calculations and tight-binding models.

Contribution

It provides a detailed analysis of disorder effects on band structure and optical properties in Mn-doped III-V semiconductors using combined computational approaches.

Findings

Mn doping causes strong electron scattering and modifies valence and conduction bands.

High donor concentration smooths the absorption edge, reducing typical III-V features.

Ab initio calculations show a tail in absorption without distinct structure.

Abstract

The substitution of Mn in the III-V diluted magnetic semiconductors leads to a strong electron scattering on impurities. Besides the features induced in the valence band by the hybridization with the Mn d-states, also the conduction band is affected by the absence of the Mn s-states at its edge. Also the high concentration of compensating donors modifies the band structure. This is shown on the absorption coefficient epsilon2(omega) of GaP doped with Mn and Se. The absorption evaluated by ab initio density functional calculations starts with a smooth tail and does not show the structure typical for III-V materials. We analyze these features and the role of the donors on model systems using the tight-binding coherent potential approach.