Defect correlations, metal-insulator transition, and magnetic order in ferromagnetic semiconductors

TL;DR

This paper investigates how defect correlations in ferromagnetic semiconductors influence their transport, magnetic properties, and energy gap stability, providing insights into the role of charged defects and their spatial arrangements.

Contribution

It demonstrates that defect correlations are essential to explain experimental observations in ferromagnetic semiconductors, linking defect distribution to their physical properties.

Findings

Defect correlations significantly affect transport and magnetic behavior.

Correlated defect distributions help maintain the energy gap upon doping.

Understanding defect arrangements is crucial for controlling material properties.

Abstract

Diluted ferromagnetic III-V semiconductors typically show a high degree of compensation. Compensation is connected to the presence of comparable densities of charged defects of either sign. This naturally leads to the development of strong correlations between defect positions during growth and annealing. We show that these correlations are required to understand the experimentally observed transport and magnetic properties as well as the persistence of the energy gap upon doping with magnetic ions.