An analysis of Zn and Se K edge XANES spectra for ZnMeSe (Me=Ni, Cr, V and Ti)

Experimental studies of X-ray Absorption Near Edge Structure (XANES) have been carried out for Se and Zn K edges in ZnNiSe, ZnCrSc, ZnVSc and ZnTiSe. A comparison is made between the experimental results for a zincblende crystalline ZnMeSe (where Me = Ni, Cr, V, and Ti) with theoretical LMTO calculations of the electron densities of states (DOS) in the conduction band for the ordered ferromagnetic phase of ZnMeSe (with 25% Me content). The agreement between the theoretical x-ray absorption edges and experimental details is not so satisfactory as for ZnMnSe and ZnFeSe, which have been obtained earlier [P.M. Lee et al., J. Phys. Condensed Matter, 6, (1994), 5771]. particularly in the intensities and the energy positions of the fine structure of the XANES experimental and theoretical spectra. However, the p-like DOS for ZnMeSe around Se and Zn ions in an energy range close to the Fermi level have been compared with success. From experimental Se and Zn K edges, hybridized contributions of the transition metals in ZnNiSe, ZnCrSe, ZnVSe and ZnTiSe have been extracted and analyzed. The comparison between ternary compounds ZnNiSe, ZnCrSe and ZnVSe and pure ZnSe, taken as standard compounds, presents a characteristic maximum of p-like contribution localized at 0.25, 1.8 and 0.25 eV below ZnSe conduction band minimum (CBM), respectively. A close correlation between theoretical p-like DOS maximum in 0 - 2 eV energy range and features subtracted from experimental data is found. The contribution of Ti in ZuSe is not observed, probably due to small solubility of Ti in ZnSe (less 1%).