Degree of p-d hybridization in ${\mathrm{Zn}}_{1\mathrm{-}\mathrm{x}}$${\mathrm{Mn}}_{\mathrm{x}}$Y (Y=S,Se) and ${\mathrm{Zn}}_{1\mathrm{-}\mathrm{x}}$${\mathrm{Co}}_{\mathrm{x}}$S alloysas studied by x-ray-absorption spectroscopy

We have measured x-ray-absorption near-edge-structure (XANES) spectra of the diluted magnetic semiconductors ${\mathrm{Zn}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Mn}}_{\mathrm{x}}$Y (Y=S,Se) and ${\mathrm{Zn}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Co}}_{\mathrm{x}}$S alloys at the Mn and Co ${\mathrm{L}}_{3,2}$ edge. Analysis of the Mn ${\mathrm{L}}_{3,2}$-edge XANES spectra for ${\mathrm{Zn}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Mn}}_{\mathrm{x}}$Y and Co ${\mathrm{L}}_{3,2}$-edge spectra for ${\mathrm{Zn}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Co}}_{\mathrm{x}}$S revealed the presence of a white-line feature in each series, whose intensity increased linearly with concentration x. The white-line feature is assigned to Mn(Co) ${2\mathrm{p}}_{3\mathrm{/}2}$ and ${2\mathrm{p}}_{1\mathrm{/}2}$photoelectron excitations to nonbonding 3d(e) states and to the relatively broadened band of Mn (Co) 3d(${\mathrm{t}}_2$)–S 3p hybridized antibonding states for the sulfides, and to Mn 3d(${\mathrm{t}}_2$)–Se 4p hybridized states for the selenides. The rate of increase of ${\mathrm{L}}_{3,2}$ white-line intensity with x is associated with the difference in the degree of p-d hybridization of states between Mn (Co) 3d and S 3p for the sulfides, and between Mn 3d and Se 4p for the selenides. Our results indicate that the magnetic-transition-metal 3d(${\mathrm{t}}_2$)–anion p hybridization is strongest for ${\mathrm{Zn}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Co}}_{\mathrm{x}}$S, intermediate for ${\mathrm{Zn}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Mn}}_{\mathrm{x}}$S and least for ${\mathrm{Zn}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Mn}}_{\mathrm{x}}$Se. From separate and Co K-edge extended x-ray-absorption fine-structure measurements on ${\mathrm{Zn}}_{1\mathrm{-}\mathrm{x}}$