Electronic structures of semiconducting alkaline-earth metal silicides

Electronic structures and densities of states of the following alkaline-earth metal silicides have been calculated using the first-principle pseudopotential method; Mg2Si, BaSi2, Ca2Si, and Sr2Si. Energetics of these in their equilibrium structures in comparison with other hypothetical structures (i.e. Ca2Si-type Mg2Si and Mg2Si-type Ca2Si) are also considered to clarify the structural change of alkaline-earth metal silicides with the promotion to the heavier elements. The semiconducting behaviors of these could be predicted though the energy band gaps calculated were about 40% of the actual measured values. Energetics of the non-stoichiometry and the atomic site of dopants for Mg2Si are also discussed.