Structural, elastic, electronic and phonon properties of scandium-based compounds ScX_3 (X = Ir, Pd, Pt and Rh): An ab initio study

摘要

Self-consistent band calculations on four compounds of the L1_2 structure are presented. The structural, elastic, electronic and phonon properties of ScX_3 (X = Ir, Pd, Pt and Rh) compounds within density functional theory have been investigated. The calculated lattice constants for those compounds are in good agreement with the available theoretical and experimental values. The elastic constants (C_(11), C_(12) and C_(44)) in L1_2 phase for ScX_3 (X = Ir, Pd, Pt and Pd) compounds are calculated using the energy-strain method. These calculated elastic constants satisfy the mechanical stability criterion and the ductility of ScX_3 (X = Ir, Pd, Pt and Rh) is predicted by Pugh's criterion. The band structure and density of states (DOS), and phonon dispersion curves have been obtained and compared with the available results as well as with existing theoretical calculations. The present band structure calculations predict that the L1_2-ScX_3 (X = Ir, Pd, Pt and Pd) compounds are metals. Finally specific heat at constant volume versus temperature is calculated and discussed using the quasi harmonic approximation.