Structural, electronic, elastic, vibrational and thermodynamic properties of U3Si2: A comprehensive study using DFT

Highlights: • The physico-chemical properties of U₃Si₂ were studied. • Involvement of 5f and 3p orbitals of U and Si atoms in U₃Si₂ analyzed by DOS. • The spin-orbit coupling effect on electronic structure of U₃Si₂ was studied. • U₃Si₂ is found to be mechanically stable and anisotropic at ambient pressure. • The vibrational and thermodynamic properties of U₃Si₂ were studied using PHONON. Uranium silicide compound is a promising candidate as low enriched uranium nuclear fuel in light water reactors. Here we report a comprehensive study on structural, electronic, elastic, vibrational and thermodynamic properties of U₃Si₂ using plane wave based density functional theory. The electron-ion interaction and exchange-correlation energy terms have been described by projected-augmented wave method and generalized gradient approximation scheme, respectively. The relativistic corrections to the total energy have been accounted by incorporating the spin-orbit interactions in the total energy calculations. The results showed good agreement between the experimental and theoretical lattice parameters. The electronic structure of U₃Si₂ compound suggests significant contribution from the 5f and 3p orbitals of U and Si atoms at the Fermi energy level, respectively. The formation energy (Δ_fH) of U₃Si₂ at 0 K, after zero point energy correction, have been estimated to be −37.40 kJ/mol. Elastic property calculation of U₃Si₂ showed mechanical stability and anisotropy at ambient pressure. In addition, the phonon calculation showed that U₃Si₂ is dynamically unstable. The temperature dependent thermodynamic properties of U₃Si₂ have also been evaluated using the phonon density of states.