Pre-edge XANES structure of Mn in (Ga,Mn)As from first principles

Abstract

Institute of Physics, Academy of Sciences of the Czech Republic, v.v.i., Cukrovarnicka 10, 162 53 Prague 6, Czech Republic * Corresponding author. Tel.: +420-220-318-459; fax: +420-233-343-184; e-mail: gonchar@fzu.cz Received February 20, 2009; accepted May 18, 2009; available on-line November 16, 2009 The X-ray absorption near-edge structure (XANES) at the Mn K-edge in the (Ga,Mn)As magnetic semiconductor was simulated using the full potential linearized augmented plane wave (FLAPW) method including the core-hole effect. The calculations were performed in the supercell scheme for a substitutional and two tetrahedral interstitial Mn sites. The resulting pre-edge absorption structures show sharp distinction between the spectra simulated for the substitutional and interstitial Mn defects, which is determined mainly by the second nearest neighbor ligands. A single feature is obtained for the substitutional Mn impurity, whereas two peaks appear for both types of interstitial defects. An interpretation of the pre-edge features is proposed. (Ga,Mn)As magnetic semiconductor / X-ray absorption near-edge structure / Substitutional / Interstitial / Defects Introduction The Mn-doped GaAs magnetic semiconductors are interesting and promising magnetic materials for potential applications in spin electronics (spintronics). The main motivation behind the preparation and investigation of these materials is the man-made combination of both semiconducting/semimetallic and ferromagnetic properties in one physical system [1-3]. Various configurations of Mn dopants affect the magnetic properties of the (Ga,Mn)As system in different ways. There are several possibilities for a Mn atom to be incorporated in GaAs, and three of them have comparable energy [4] . The substitutional Mn atoms, Mn