Electronic structure of the superconducting layered ternary nitrides CaTaN2 and CaNbN2

JOSEP M. OLIVA; RUBEN WEHT; PABLO ORDEJON; ENRIC CANADELL

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Año: 2000 vol. 62 p. 1512 - 1515

1098-0121

The electronic structure of the layered ternary nitrides CaMN2 (M = Ta, Nb) has been studied and the results are compared with those for the related LiMoN2 phase. It is shown that the former are two-dimensional metals, with a Fermi surface very similar to that of the 1T-TaX2 (X = S, Se) dichalcogenides, whereas the latter is a three-dimensional metal. The three phases show strong covalent bonding within the layers but ionic bonding with the alkali atom sheets.