Investigation of structural, opto-electronic and thermoelectric properties of titanium based chloro-perovskites XTiCl (X = Rb, Cs): a first-principles calculations.

Perovskites are a significant class of materials with diverse uses in modern technology. The structural, electronic, elastic, thermoelectric, and optical properties of RbTiCl and CsTiCl perovskites were estimated using the FP-LAPW method within the framework of density functional theory. The exchange-correlation energy of both analyzed systems was calculated using the Generalized Gradient Approximation (GGA) functional. The structures are optimized and lattice constants of 5.08 Å and 5.13 Å are found for XTiCl (X = Rb, Cs), respectively. The structural analysis reveals that they have cubic symmetry. Their half metallic nature was proved by their metallic nature in one spin channel and semiconducting nature in the opposing spin channel. Densities of states are calculated to predict the interaction of orbitals of distinct atoms in the compounds. From the results of optical response, it is found that these compounds show high optical absorption in the visible region of light. Moreover, thermoelectric properties of the studied materials are calculated as a function of chemical potential at different temperatures using the theory of semi-classical Boltzmann transport within BoltzTrap code. The thermoelectric response shows that the investigated compounds as p-type can be beneficial in overcoming the global warming issue.