Crystal structures and electronic properties of MC₂ (M = Mg, Ca, Sr, Ba) by comparative studies based on ab-initio calculations

Band structures and electronic properties of MC₂ were studied by density functional theory (DFT) calculation. The chemical bonds are admixed with an ionic bond between M²⁺ and C₂^{2 -} and a strong covalent bond in anion clusters. Orbital hybridization effect is much stronger for ions with smaller radius. Relatively flat dispersion relations of band structures are indicated the localized bonding state and population analysis provided further information on this aspect. The results of DOS show the valence band near the E_F is all dominated by 2p orbit of carbon atoms and metals play an important role in conduction band.