Electronic Structures of Antiperovskite Superconductor MgCNi${}_3$ and Related Compounds

Abstract

Electronic structure of a newly discovered antiperovskite superconductor MgCNi${}_3$ is investigated by using the LMTO band method. The main contribution to the density of states (DOS) at the Fermi energy $E_{\mathrm{F}}$ comes from Ni 3$d$ states which are hybridized with C 2$p$ states. The DOS at $E_{\mathrm{F}}$ is varied substantially by the hole or electron doping due to the very high and narrow DOS peak located just below $E_{\mathrm{F}}$. We have also explored electronic structures of C-site and Mg-site doped MgCNi${}_3$ systems, and described the superconductivity in terms of the conventional phonon mechanism.

3 pages, presented at ORBITAL2001 September 11-14, 2001 (Sendai, JAPAN)