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.