Pressure Effect on Structural and Phonon Properties of Mixed Alloys Compounds

Abstract

We report pressure induced structural phase transition, elastic and thermal properties of concentrations of UXLa1-XS (x= 0.80, 0.60 and 0.50) compound, using modified inter-ionic potential theory (MIPT), which parametrically includes the effect of coulomb screening. The calculated equation of state, phase transition pressure, bulk modulus and volume collapse are agree well with the available theoretical or experimental findings. We have also reported the second order elastic constants and Debye temperature of this compound for first time. We have also reported the Phonon properties of UxLa1-xS (x = 0.80, 0.60, 0.50) compounds by using breathing shell model (BSM). The present model includes breathing motion of electron shells of rare earth atom due to f-d hybridization. The calculated phonon dispersion curves of UxLa1-xS are presented follow the same trend as observed in uranium chalcogenides. We have reported doping effect of La on phonon frequencies at X and L-points for the first time. The LO-TO splitting increases as decreasing concentration of La.Keywords: Phase Transition, Elastic Properties, Debye Temperature, Phonon Dispersion