Structural, elastic, electronic and vibrational properties of BaRh2P2 and SrIr2As2 superconductors: A DFT study

Abstract

The structural, elastic, electronic, Vickers-Hardness, vibrational, Optical and thermo dynamical properties of potentially technologically important superconductors BaRh2P2 and SrIr2As2 are calculated using density functional theory (DFT) with CASTEP code for the first time. The structural and other physical properties of BaRh2P2 and SrIr2As2 are compared with the results where available and show well accord. The phonon dispersion curve is calculated and the dynamical stability of this compound is investigated. Both the compounds show mechanically stable under the Born stability conditions. For the above condition BaRh2P2 behaves ductile nature and SrIr2As2 indicates the brittle nature. The Mulliken dislocation bonding population and charge density maps show stronger bond between As-Ir compared with Ir-Ir bond. The overall superior conversation reflects that the chemical bonding in BaRh2P2 and SrIr2As2 superconductors can be denominated as an extremely anisotropic connection between ionic, covalent and metallic interactions. At the Fermi level valence band and conduction bands overlapped, so the compounds are metal. From the Fermi surface and charge density map it is observed that both ionic and covalent bond exist. Vickers hardness reveals the both superconductors relatively soft with compare to Diamond. The optical and acoustic modes are observed clearly. We calculate the Helmholtz free energy (F), internal energy (E), entropy (S), and specific heat capacity (Cv) from the phonon density of states. Various optical parameters are also calculated. The reflectance spectrum shows that this compound has the potential to be used as an efficient solar reflector. Debye temperature of BaRh2P2 and SrIr2As2 superconductors are 273.91 K and 341.03 K calculated by using present elastic constants data. The superconducting parameter indicates the phonon-mediated medium coupled BCS superconductors. The acquired results in present investigation could provide a great spur for future studies.