Possible nonactivated conductivity of the low-dimensional ternary nitride Ca(2)GeN(2)

The electronic structure of the recently reported ternary nitride Ca(2)GeN(2) has been studied by means of first-principles density functional calculations. The relatively short nonbonded Ge...Ge contacts along the direction approximately perpendicular to the plane of the bent GeN(2) units confer a large dispersion to the energy bands based on the antibonding pi-type level of GeN(2). This feature as well as the smaller but non-negligible interactions along the perpendicular directions suggests that this material, despite being built from discrete units, may exhibit a metallic behavior. This study suggests that the nature of the alkaline-earth atom has a crucial influence on the electrical conductivity of this type of phase.