Electronic structure, magnetism, and superconductivity ofMgCxNi3

The electronic structure of the newly discovered superconducting perovskite ${\mathrm{MgCNi}}_3$ is calculated using the LMTO method. The states near the Fermi energy are found to be dominated by $\mathrm{Ni}-d.\mathrm{}$ The Stoner factor is low while the electron-phonon coupling constant is estimated to be about 0.5, which suggests that the material is a conventional type of superconductor where $T_c$ is not affected by magnetic interactions. However, the proximity of the Fermi energy to a large peak in the density of states in conjunction with the reported nonstoichiometry of the compound has consequences for the stability of the results.