Temperature-dependent resistivity of ferromagnetic GaMnAs: Interplay between impurity scattering and many-body effects

TL;DR

This paper investigates how impurity scattering and many-body effects influence the temperature-dependent resistivity of ferromagnetic GaMnAs, revealing the importance of spin fluctuations in resistivity behavior.

Contribution

It introduces a combined theoretical approach using memory function formalism and density-functional theory to analyze resistivity in GaMnAs, highlighting the role of spin fluctuations.

Findings

Coulomb impurity scattering alone cannot explain resistivity drop.

Spin fluctuations significantly impact resistivity below the transition.

Impurity scattering and many-body effects are both crucial for accurate modeling.

Abstract

The static conductivity of the dilute magnetic semiconductor GaMnAs is calculated using the memory function formalism and time-dependent density-functional theory to account for impurity scattering and to treat Hartree and exchange interactions within the hole gas. We find that the Coulomb scattering off the charged impurities alone is not sufficient to explain the experimentally observed drop in resistivity below the ferromagnetic transition temperature: the often overlooked scattering off the fluctuations of localized spins is shown to play a significant role.