Photoinduced magnetism in the ferromagnetic semiconductors

TL;DR

This paper investigates how incident light can increase the magnetic transition temperature in ferromagnetic semiconductors like EuS by mediating additional magnetic interactions through photoexcited carriers, aligning theoretical predictions with experimental observations.

Contribution

It introduces a model combining a Heisenberg Hamiltonian with carrier interactions to explain light-induced enhancements of $T_c$ in ferromagnetic semiconductors.

Findings

Photoexcited carriers enhance magnetic interactions.

Model predicts small increase in $T_c$ consistent with experiments.

Light can be used to control magnetic properties in semiconductors.

Abstract

We study the enhancement of the magnetic transition temperature $T_c$ due to incident light in ferromagnetic semiconductors such as EuS. The photoexcited carriers mediate an extra ferromagnetic interaction due to the coupling with the localized magnetic moments. The Hamiltonian consists of a Heisenberg model for the localized moments and an interaction term between the photoexcited carriers and the localized moments. The model predicts a small enhancement of the transition temperature in semi-quantitative agreement with the experiments.