First-principles calculations to investigate physical properties of single-cubic (Ba0.82K0.18)(Bi0.53Pb0.47)O3 novel perovskite superconductor

Abstract

In the present study, the pseudopotential plane-wave (PP-PW) pathway in the scheme of density functional theory (DFT) is utilized to investigate the various unexplored physical properties of (Ba0.82K0.18)(Bi0.53Pb0.47)O3 (BKBPO) single perovskite superconductor. We have analyzed mechanical properties, elastic constants, and moduli at ambient temperature with zero and elevated pressures (up to 25 GPa) using the CASTEP code at equilibrium conditions as well. The calculated values of Poisson’s ratio, Pugh’s indicator, and Cauchy pressure show that the studied superconductor is ductile in nature at ambient conditions. The calculated machinability index and hardness values of BKBPO perovskite indicate its superior industrial applications compared to similar perovskites. The compound might be considered a promising thermal barrier coating (TBC) material based on Young’s modulus (E), and thermal shock coefficient (R) data. We also have investigated the anisotropic nature incorporating both the theoretical indices and graphical representations in 2D and 3D dimensions, which express a high level of anisotropy of the studied compound. The flatness of the energy bands near EF is a sign of Van-Hf singularity that might increase the electron pairing and origination of high-TC superconductivity. The computed band structure exhibits its metallic characteristics which is confirmed by the band overlapping in the diagram. A band of DOS is formed for the strong hybridization of the constituent elements where the O-2p orbital electrons contribute most dominantly at EF in contrast to all orbital electrons. The orbital electrons at the EF are seen maximum from both the partial density of states and charge density mapping. The coexistence of the electron and hole-like Fermi sheets exhibits the multi-band nature of the BKBPO superconductor. On the other hand, Fermi surfaces with flat faces promote transport features and Fermi surface nesting as well. The calculated value of the electron-phonon (e-ph) coupling constant (λ = 1.46) is slightly lower than that of isostructural superconductors, which indicates that the studied BKBPO can be treated as a strongly coupled superconductor identical to the previously reported isostructural perovskite superconductors. Furthermore, the thermodynamic properties have been evaluated and analyzed at elevated temperature and pressure by using harmonic Debye approximation (QHDA).