Curie temperature versus hole concentration in field-effect structures of Ga1-xMnxAs

TL;DR

This study explores how the Curie temperature in GaMnAs thin films depends on hole concentration, revealing a power-law relationship influenced by electric fields and modeled by a p-d Zener approach.

Contribution

It demonstrates a quantitative relationship between Curie temperature and hole concentration in ferromagnetic semiconductors, incorporating nonuniform hole distribution effects.

Findings

Curie temperature scales as p^{0.19}

Electric field modulates hole concentration and magnetic properties

p-d Zener model explains the observed dependence

Abstract

The Curie temperature TC is investigated as a function of the hole concentration p in thin films of ferromagnetic semiconductor (Ga,Mn)As. The magnetic properties are probed by transport measurements and p is varied by the application of an external electric field in a field-effect transistor configuration. It is found that TC is proportional to p^{\gamma}, where the exponent \gamma = 0.19 \pm 0.02 over a wide range of Mn compositions and channel thicknesses. The magnitude of gamma is reproduced by a p-d Zener model taking into account nonuniform hole distribution along the growth direction, determined by interface states and the applied gate electric fields.