Results of optical and thermal study of lead sulfide (PbS), Barium sulfide (BaS) and their ternary (Pb1-xBaxS) (0≤x≤1)alloys

Abstract

Abstract We have simulated different physical properties of Pb1-xBaxS (0\u202f≤\u202fx\u202f≤\u202f1), among them: PbS, BaS, Pb0.75 Ba0·25S, Pb0·5Ba0·5S, Pb0·25Ba0·75S semiconductors using the (FP-LAPW) method. We calculated energetic gap by using the GGA, EV-GGA, and the mbj approximations. We found that Pb1-xBaxS is a direct band gap semiconductor. The observed critical temperature is Tc\u202f=\u202f731K for Pbl-xBaxS alloys. The refractive indexes n decreases from 3.87 to 2.25, with the increasing of Ba concentration. To study the thermal effects, the temperature effect on the lattice parameters, thermal expansions, heat capacities the quasi-harmonic Debye model is applied. The Debye temperatures, is determined from the non-equilibrium Gibbs functions. θD is nearly constant from 0 to 100\u202fK.