Regular Article

Theoretical analysis of the structural, electronic, optical and thermodynamic properties of trigonal and hexagonal Cs₃Sb₂I₉ compound

¹ Laboratory for Developing New Materials and Their Characterizations, University of Setif 1, Algeria
² Department of Physics, Faculty of Science, University of M’sila, Algeria

^a e-mail: saadi.berri@univ-msila.dz

Received: 18 March 2020
Received in final form: 9 July 2020
Accepted: 25 August 2020
Published online: 5 October 2020

Abstract

The structural, electronic, optical and thermodynamic properties of Cs₃Sb₂I₉ compound with 0-D dimer form (hexagonal SP; P63∕mmc, no. 194) and the 2-D layered form (trigonal SP; P3m̄1, no. 164) phases have been investigated and reported using both FP-LAPW and PP-PW methods. Besides, the thermodynamic properties of the materials of interest have been studied using the quasi-harmonic Debye model accommodating the lattice vibrations effects. The obtained lattice parameters for dimer and layered phase reveal very good accord with experiment. The computed electronic band structures show that in the dimer phase the material of interest is an indirect band-gap (k–Γ) semiconductor, whereas it is a direct band-gap (Γ–Γ) in the layered phase. The semiconducting material Cs₃Sb₂I₉ of interest was found to be stable against volume change of 0 to +14%. Moreover, the optical properties of the material in question are also examined and discussed. The effect of pressure and temperature on the studied properties is found to be highly effective in tuning some of the macroscopic properties of the compound in question.