Electronic structure of CsAu

Self-consistent non-relativistic and relativistic LMTO band structure calculations have been carried out for CsAu. In the non-relativistic model CsAu is a metal, whereas — in agreement with experiments — the relativistic calculations predict CsAu to be a semiconductor. The gap is not caused by the spin-orbit coupling. The importance of the core-like Cs-5s and Cs-5p states for the alloy formation is discussed, and charge distribution calculations are used to illustrate the ionic nature of the bonding.