Structural, Mechanical, Electronic, and Optical Properties of CsCdX3 (X = Cl, Br, and I): A Comparative Study Using First Principle Calculation

This study presents a comparison of structural, optical, mechanical, and electronic characteristics of CsCdX3 (X = Cl, Br, and I) by employing first principle calculations. We performed this calculation using the general gradient approximation (GGA) scheme within the Perdew-Berke-Ernzerhof (PBE) functional, which is carried out by the Cambridge Serial Total Energy Package (CASTEP) system. The computation's validity is validated by a comparison of accessible mathematical and experimental findings. The computed lattice constants show excellent consistency with those obtained from the theoretical calculation and experimental techniques. The computed result explicates that when the larger halogen is substituted for the smaller one, the cell volume and lattice parameter of CsCdX3 (X = Cl, Br, and I) increase. The obtained mechanical characteristics evidence that CsCdX3 (X = Cl, Br, and I) compounds are ductile, and ductility increases with the replacement of Cl with Br and I, respectively, and CsCdI3 exhibits the highest amount of ductility. Indirect bandgap semiconductor to metallic transition is found in the energy band diagrams when I occupies the X site of CsCdX3 instead of Cl and Br. Furthermore, the absorption coefficient, the dielectric constant, conductivity, and refractive index demonstrate that when Cl is replaced by I and Br, redshift occurs in the optical spectra. Among the compounds, the reflectivity of CsCdI3 is the highest in the IR region, making CsCdI3 suitable as an IR reflector. But in the UV region, CsCdCl3 could be suitable as a UV reflector.