First-principles investigation of structural, electronic and optical properties of quasi-one-dimensional barium cadmium chalcogenides Ba2CdX3 (X = S, Se, Te) using HSE06 and GGA-PBE functionals

Abstract

Structural, electronic and optical properties of quasi-one-dimensional barium cadmium chalcogenides Ba2CdS3, Ba2CdSe3 and Ba2CdTe3 are studied using density functional theory. Structural properties of these materials are investigated by incorporating Van der Waals correction with PBE exchange correlation functional. Results of structural analysis are in good agreement with the previously reported experimental observations and confirm the quasi-one-dimensional structure of the compounds. Ba2CdX3 chalcogenide structures crystallize in orthorhombic phase with space group Pnma-D2h16. Band structure calculations with HSE06 show that Ba2CdSe3 and Ba2CdTe3 are wide bandgap materials with direct bandgap of 2.56 eV for Ba2CdSe3 and 2.16 eV for Ba2CdTe3. Ba2CdS3 is an insulator with direct bandgap 3.16 eV. Optical properties are investigated by calculating the refractive index, birefringence, dichroism, dielectric function and absorption coefficient using the HSE06 method. Ba2CdX3 materials exhibit large optical anisotropy with considerable birefringence and dichroism. The comparatively high values of absorption coefficients, extinction coefficients, birefringence and dichroism make Ba2CdX3 materials suitable for applications as polarizers and sensing devices, while the large direct bandgaps indicate that they are promising candidates in photovoltaic applications.