Newly synthesized A-site ordered cubic-perovskite superconductor (Ba0.54K0.46)4Bi4O12: A DFT investigation

Abstract

Theoretical investigation of the elastic, electronic, superconducting, and thermal properties of newly synthesized cubic perovskite superconductor (Ba0.54K0.46)4Bi4O12 (BKBO) is carried out by generalized gradient approximation (GGA) which is based on density functional theory (DFT). Comparisons are made with two recently discovered Bi-basedAA'3B4O12-typeperovskite superconductors (Na0.25K0.45)Ba3Bi4O12 and (K1.00)(Ba1.00)3(Bi0.89Na0.11)4O12 and with available experimental data of (Ba0.54K0.46)4Bi4O12 perovskite. The elastic constants, mechanical stability, machinability index, Poisson's ratio, Cauchy's pressure, elastic anisotropy, Vickers hardness and Peierls stress are all investigated. The electronic band structure, density ofstates, features of Fermi surface and distributions of charge density are studied as well. Hybridization involving Bi-6s and O-2p orbitals (dominant contribution) is observed at EF similar to that seen in the previously published Bi-based perovskite superconductors. Both electron and hole like Fermi surfaces are seen which exhibits multiband nature of the superconductor. The flatness of the Fermi surface promotes transport features in Bi-based perovskite superconductor. The distribution of charge density of BKBO is basically spherical around all ions which essentially reveal the ionic characteristics of the material. The thermal properties, namely, Debye temperature, specific heat capacities and volume thermal expansion coefficient as a function of temperature areanalyzed with the help of quasi-harmonic Debye model. The estimated electron-phonon (e-ph) coupling constant of (Ba0.54K0.46)4Bi4O12 indicates its typical nature of a strongly coupled superconductor similar to the previously studied isostructural perovskites superconductors.