Electronic structure of CsAu

Abstract

The energy bandstructures and charge distributions in CsAu, which is known to show an interesting semiconducting behaviour, are calculated using the APW method. An effect of the charge transfer is taken into account by means of a self-consistent calculation. The calculated bands are characterised by a strong hybridisation of the Cs d state and the Au sp state. They show a metallic behaviour in disagreement with experiments. It has been found that the relativistic energy shifts contribute to the formation of the energy gap between the valence band consisting mainly of the Au s state and the conduction band. The spin-orbit interaction plays a minor role. The way in which CsAu undergoes a nonmetal-metal transition under pressure is suggested.