Electronic structure of Se, Se–Te, and Se–Te–Sb systems: Some observations from the x-ray spectroscopy and ab initio calculations

Abstract

Electronic structures of Se, Se80Te20, and Se80−xSbxTe20(0≤x≤9) systems have been investigated using x-ray photoelectron spectroscopy and x-ray absorption near edge spectroscopy (XANES). The experimental results show strong Se–Se and Se–Te interaction as well as antimony dilution effects in the ternary alloy. The interpretation of the results is assisted by theoretical calculations. The densities of states for the energy bands have been evaluated with the full potential augmented plane wave method based on the density functional theory (DFT) and the real-space multiple scattering (RSMS) approach using small clusters of model crystal structures. The ab initio calculation methods for the XANES spectra of Se, Se80Te20, and Se80−xSbxTe20(0≤x≤9) systems are compared with the experimental data. It is found that the DFT calculation provides better agreement with the pre-edge resonance, while RSMS yields good agreement with the postedge region. The interplay of x-ray spectroscopy results and theory is discussed.