Structural, Elastic, Electronic, Optical and Thermodynamic Properties of ThCr2Si2-Type Os-Based Superconductors MOs2P2 (M= Sr and Ba): A DFT Study
Keywords:
SrOs2P2 and BaOs2P2 compounds, DFT study, elastic properties, vickers hardness, optical properties, thermodynamic propertiesAbstract
The structural, mechanical, electronic, Vickers-hardness, optical and thermodynamic properties of industrially important superconductors SrOs2P2 and BaOs2P2 are investigated employing the density functional theory (DFT) through the CASTEP code for the first time. The optimized structural parameters and other physical properties of SrOs2P2 and BaOs2P2 show good agreement with experimental results and same type of compounds where available. Mechanical and dynamical stability of both the phases is ensured by the analysis of the elastic constant data. According to the calculated values of Pugh’s ratio and Poisson’s ratio the compound BaOs2P2 shows ductile nature and SrOs2P2 shows brittle nature. Both the compounds reveal anisotropic nature where the elastic anisotropy of SrOs2P2 is higher than that of BaOs2P2. The hardness of SrOs2P2 and BaOs2P2 is evaluated to be 9.16 GPa and 7.32 GPa correspondingly representing the relative hardness of SrOs2P2 than that of BaOs2P2 compound. The investigation of the electronic band structure and density of states (DOS) specifies the metallic nature of both the compounds. The analysis of DOS, Mulliken atomic populations and total charge density revel a complex bonding in SrOs2P2 and BaOs2P2 with ionic, covalent and metallic characteristics. The analysis of the dielectric function also ensures the metallic behavior of these compounds. The reflectivity is found to be high which reveals that MOs2P2 (M= Sr and Ba) having the same characteristics could be good candidate materials to reduce solar heating up to ~11 eV. Finally the Debye temperature of SrOs2P2 and BaOs2P2 has been calculated by using the elastic constant data to be 305.84 K and 287.92 K respectively.