DFT Study of Structural, Elastic, Electronic, and Thermodynamic Properties of Compounds Cs2TiCl6 and Cs2TiBr6

Abstract

We investigate the electronic, structural, elastic, and thermodynamic properties of Cs₂TiX₆ (X = Cl and Br) using DFT calculations. The generalized gradient approximation in the Perdew–Burke–Ernzerhof (PBE) form is used in this work to investigate the properties of the above compounds. The calculated lattice parameters of these compounds are in good agreement with the experimental data. The elastic constants obtained confirm the mechanical stability of Cs₂TiX₆ compounds. The calculated Pugh’s and Poisson’s ratios revealed that the Cs₂TiCl₆ and Cs₂TiBr₆ compounds are brittle materials. The band gaps of Cs₂TiCl₆ and Cs₂TiBr₆ compounds are, respectively, 2.27 and 1.45 eV. The thermodynamic properties of these compounds have also been investigated, and the thermodynamic parameters such as heat capacity (C_V) and the thermal expansion (α) were calculated. The obtained values of C_V were found to be 125 and 224 J mol^–1 K^–1 for Cs₂TiCl₆ and Cs₂TiBr₆, respectively. Debye temperatures for the studied compounds were also computed and discussed.