Electronic structure and electron transport properties of calcium-zinc amorphous alloys and several intermetallic compounds

Abstract

The electronic structure and electron transport properties of the CaxZn100-x (x=45, 50, 64 and 75) amorphous alloys have been studied through the measurements of X-ray photoemission spectroscopy (XPS), low-temperature specific heats, magnetic susceptibility, electrical resistivity, Hall coefficient and thermoelectric power. The XPS spectra and low-temperature specific heats were also measured for Ca3Zn, CaZn, CaZn2 and CaZn5 intermetallic compounds. The prepeak was observed in the X-ray diffraction spectrum for the Ca75Zn25 amorphous alloy. this was taken as strong support for the realistic atomic structure model proposed by Hafner and Tegze (1989). It is found that the valence band structure deduced from the XPS spectrum and electronic specific heat coefficient agrees with that derived from the self-consistent band calculations based on the realistic atomic structure. It is concluded that, in spite of the enhancement of the density of states at the Fermi levels due to the sizeable contribution of the Ca 3d states, the temperature dependence of the resistivity and Hall coefficient can be explained by assuming that Zn 4p and Ca 4p electrons at the Fermi level are mostly responsible for electron conduction.