Hybridization of the 3d states of transition metals with the states of the ZnS matrix

Abstract

The near-edge soft x-ray absorption spectra of ${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{M}}_{\mathrm{x}}$S compounds (where M is Mn, Fe, Co, and Ni, and x ranges to the solubility limit) have been obtained by measuring the total electron yield (photoelectron, Auger and secondary) from the sample in an ultrahigh vacuum (UHV) sample chamber using x-rays from beam line 6.3.2, a bending magnet beamline at the Advanced Light Source (ALS). The high spectral resolution of the beamline in the 50--1000 eV region allowed detailed measurements of S-${\mathrm{L}}_{2,3}$ and transition metal ${\mathrm{L}}_{3}$ absorption spectra. The study of d and s antibonding states in ${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{M}}_{\mathrm{x}}$S compounds provided evidence that 3d states of transition metals participate in the formation of ionic-covalence bonding between M-S. Furthermore, it was found that the ability of 3d electrons to participate in bonding decreases with increasing 3d orbit filling. As the 3d orbit becomes more closed, the 3d electrons assume a more corelike character. The evidence of these behaviors can be seen in the metal and sulfur L absorption spectra as well as in the charge transfer values calculated from the energy shifts in transition metal K edges. These findings provided an explanation for the drastic decrease in the solubility of these particular metals in the ZnS matrix.