Ab-initio study on structural, elastic, electronic and optical properties of iron-based superconductor

Abstract Using the plane-wave ultrasoft pseudo-potential technique, which is based on the first-principle density functional theory with generalized gradient approximation, the structural, elastic, electronic, and optical properties of FeSe are investigated. The calculated structural parameters show a good agreement with the experimental and other theoretical results. The optimized lattice parameters, independent elastic constants (C11, C12, C13, C33, C44, and C66), bulk modulus B, compressibility K, shear modulus G, and Poisson’s ratio ν, as well as the band structures, total and atom projected densities of states, and finally the optical properties of FeSe have been evaluated and discussed. The band structure and density of states show that this phase has metallic behavior and the major contribution comes from Fe-3d states. Further, the first time investigated optical functions reveal that the reflectivity is high in the IR-UV region up to 19.5 eV, showing this to be promising coating material.