Structural, elastic and electronic properties of superconducting anti-perovskites MgCNi3, ZnCNi3 and CdCNi3 from first principles

Abstract

First principle total energy calculations using the full potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA) for the exchange-correlation potential were performed to investigate the systematic trends for structural, elastic and electronic properties of the family of superconducting anti-perovskites MCNi3 depending from the type of M cations (M are Mg, Zn and Cd). In result the optimized lattice parameters, independent elastic constants (C11, C12 and C44), bulk modulus B, compressibility β, shear modulus G and tetragonal shear modulus G′ are evaluated. Further, for the first time the numerical estimates of a set of elastic parameters (bulk and shear modulus, Young’s modulus Y, Poisson’s ratio (ν), Lamé’s coefficients (μ, λ)) of the polycrystalline superconducting MCNi3 ceramics (in framework of the Voigt–Reuss–Hill approximation) were performed. Besides, the band structures, densities of states (DOS), total and site-projected l-decomposed DOS at the Fermi level, the shapes of the Fermi surfaces, the Sommerfeld’s coefficients and the molar Pauli paramagnetic susceptibility for these anti-perovskites were obtained and analyzed in comparison with the available theoretical and experimental data.