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

Chem. Met. Alloys 2 (2009) 34-38

https://doi.org/10.30970/cma2.0085

Nataliya A. GONCHARUK, Jan KUČERA, Ludvík SMRČKA

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.

Normalized ab-initio Mn K-edge XANES spectra simulated including the core-hole effect in the 64-atom (Ga,Mn)As supercell for three different Mn sites in the substitutional (Mn_Ga^sub) and two tetrahedral interstition positions (Mn_As^int and Mn_Ga^int). Energies of spectra are shifted by the experimental transition energy of a Mn atom, E_o = 6539 eV. The grey region indicates the pre-edge part of absorption spectra (peaks A and B), which is shown in detail in the insert.

Keywords

(Ga,Mn)As magnetic semiconductor / X-ray absorption near-edge structure / Substitutional / Interstitial / Defects