Electronic Structure of the Dilute Magnetic Semiconductor $Ga_{1-x}Mn_xP$ from Hard X-ray Photoelectron Spectroscopy and Hard X-ray Angle-Resolved Photoemission

TL;DR

This study investigates the electronic structure of the dilute magnetic semiconductor GaMnP using advanced photoelectron spectroscopy techniques, revealing impurity-induced band modifications and similarities with GaMnAs, supported by theoretical calculations.

Contribution

It provides new experimental insights into Mn doping effects in GaP and compares these with theoretical models, highlighting the emergence of impurity bands and electronic structure changes.

Findings

Mn doping broadens valence bands and introduces impurity states.

Experimental data aligns well with one-step photoemission calculations.

GaMnP shows electronic similarities to GaMnAs, especially in core-level spectra.

Abstract

We have investigated the electronic structure of the dilute magnetic semiconductor (DMS) $Ga_{0.98}Mn_{0.02}P$ and compared it to that of an undoped $GaP$ reference sample, using hard X-ray photoelectron spectroscopy (HXPS) and hard X-ray angle-resolved photoemission spectroscopy (HARPES) at energies of about 3 keV. We present experimental data, as well as theoretical calculations, in order to understand the role of the Mn dopant in the emergence of ferromagnetism in this material. Both core-level spectra and angle-resolved or angle-integrated valence spectra are discussed. In particular, the HARPES experimental data are compared to free-electron final-state model calculations and to more accurate one-step photoemission theory. The experimental results show differences between $Ga_{0.98}Mn_{0.02}P$ and $GaP$ in both angle-resolved and angle-integrated valence spectra. The $Ga_{0.98}Mn_{0.02}P$ bands are broadened due to the presence of Mn impurities that disturb the long-range translational order of the host $GaP$ crystal. Mn-induced changes of the electronic structure are observed over the entire valence band range, including the presence of a distinct impurity band close to the valence-band maximum of the DMS. These experimental results are in good agreement with the one-step photoemission calculations, and a prior HARPES study of $Ga_{0.97}Mn_{0.03}As$ and $GaAs$ (Gray et al. Nature Materials 11, 957 (2012)), demonstrating the strong similarity between these two materials. The Mn 2p and 3s core-level spectra also reveal an essentially identical state in doping both $GaAs$ and $GaP$.