Chemical bonding and electronic structure of Pd2Si

Abstract

The chemical bonding and electronic properties of Pd2Si have been investigated by measuring ultraviolet photoemission spectroscopy and Auger electron spectroscopy transitions involving both core and valence electrons for Pd, Si, and Pd2Si. The spectra have been interpreted based on partial state densities calculated for Pd-Si compounds. In the silicide, the d states of the Pd interact strongly with the p states of the Si. The resulting p-d hybrid complex is composed of Pd d states lying almost entirely below EF with the central peak at - 2.75 eV and two groups of Si states separated by ∼5 eV. The lower-lying group of Si states forms the Si 3p-Pd 4d bonding levels, while the higher-lying group near EF forms the corresponding antibonding states. The compound stoichiometry can change the position of the d peak as well as the occupation of the antibonding states, thus affecting the phase stability of the compound. Such stoichiometry variations are consistent with filling of the d-p complex in an almost rigid-band-like manner. The results obtained in this study can be used to account for the transport properties of Pd2Si. © 1980 The American Physical Society.