Magneto-optical spectroscopy of (Ga,Mn)N epilayers

TL;DR

This study uses magneto-optical spectroscopy to analyze (Ga,Mn)N epilayers, revealing detailed magnetic interactions and the giant Zeeman effect caused by exchange interactions between Mn$^{3+}$ ions and carriers.

Contribution

It provides a detailed analysis of the Zeeman effect and exchange interactions in (Ga,Mn)N epilayers, including parameters of effective Hamiltonians and evidence of ferromagnetic spin-hole interactions.

Findings

Precise determination of Mn$^{3+}$ internal transition parameters.

Observation of the giant Zeeman effect due to exchange interactions.

Identification of ferromagnetic spin-hole interaction.

Abstract

We report on the magneto-optical spectroscopy and cathodoluminescence of a set of wurtzite (Ga,Mn)N epilayers with a low Mn content, grown by molecular beam epitaxy. The sharpness of the absorption lines associated to the Mn$^{3+}$ internal transitions allows a precise study of its Zeeman effect in both Faraday and Voigt configurations. We obtain a good agreement if we assume a dynamical Jahn-Teller effect in the 3d$^{4}$ configuration of Mn, and we determine the parameters of the effective Hamiltonians describing the $^{5}T\_{2}$ and $^{5}E$ levels, and those of the spin Hamiltonian in the ground spin multiplet, from which the magnetization of the isolated ion can be calculated. On layers grown on transparent substrates, transmission close to the band gap, and the associated magnetic circular dichroism, reveal the presence of the giant Zeeman effect resulting from exchange interactions between the Mn$^{3+}$ ions and the carriers. The spin-hole interaction is found to be ferromagnetic.