Modeling huge photoinduced spin polarons in intrinsic magnetic semiconductors

TL;DR

This paper investigates photoinduced spin polarons in intrinsic magnetic semiconductors using Monte Carlo simulations and an analytical Weiss field model, revealing how polaron size varies with magnetic order and temperature.

Contribution

It introduces an analytical Weiss field model to estimate spin polaron sizes, complementing Monte Carlo simulations and enabling quick predictions in magnetic semiconductors.

Findings

Photoinduced spin polarons are efficiently generated up to the phase transition in antiferromagnetic semiconductors.

Larger spin polarons are photoinduced near the phase transition in ferromagnetic semiconductors.

The Weiss model provides quick estimates of polaron sizes despite less detail than Monte Carlo simulations.

Abstract

In intrinsic magnetic semiconductors, the absorption of a single photon can generate a spin polaron, whose magnetic moment reaches many thousands of Bohr magnetons [1.2]. Here we investigate photoinduced spin polarons, using Monte Carlo simulations. In antiferromagnetic semiconductors, photoinduced spin polarons are most efficiently generated in the whole temperature interval up to the phase transition, whereas in ferromagnetic semiconductors much larger spin polarons can be photoinduced, but only around the phase transition temperature. Because Monte Carlo simulations are computationally expensive, we developed an analytical model, based on the Weiss field theory. Although the Weiss model does not provide as much information as a Monte Carlo simulation, such as spin texture and fluctuations, it yields formulas that can be used to estimate instantly the expected photoinduced spin polaron size in many intrinsic magnetic semiconductors.