Ground state, phonon spectrum, and superconducting properties of the cubic inverse perovskite CuNNi3

Abstract

Using a first-principles approach, based on pseudopotentials and the density functional theory, we have investigated the origin of superconductivity in the cubic inverse perovskite CuNNi3. The electronic results reveal that the states around the Fermi level are mainly derived from Ni d orbitals. The average electron phonon coupling constant and the logarithmically averaged frequency are found to be 0.678 and 165.53 K, respectively. The superconducting transition temperature is estimated as 3.34 K, in good agreement with the experimentally reported value of 3.2 K. We thus conclude that this material is a conventional phonon-mediated superconductor. (C) 2014 Elsevier B.V. All rights reserved.