By means of density functional theory, the electronic structure of the MgB2 superconductor was characterized and compared with that of the related iso-structural systems: AlB2, ZrB2, NbB2, and TaB2. Using the full potential-linearized augmented plane wave method and the generalized gradient approximation, the electronic density distribution, density of states and band structures were obtained for the compounds. The electrical conductivity, which could not be easily measured in the c-direction, was calculated, in the relaxation time approximation, using band structure results. It was found that the 2-dimensional crystal structure form of the metallic diborides was also reflected by the electronic charge distribution. This 2D pattern was not reproduced in the electrical conductivity as it was in high-TC cuprates. The calculations indicated a bulk, yet anisotropic, conductivity for all of the compounds.

Comparative Study of the Electronic Structure of Alkaline-Earth Borides (MeB2; Me = Mg, Al, Zr, Nb, and Ta) and their Normal-State Conductivity. P.de la Mora, M.Castro, G.Tavizon: Journal of Solid State Chemistry, 2002, 169[2], 168-75