Predicting the stable rhodium based chalcopyrites with remarkable optical properties

Abstract

The ternary chalcopyrite compounds and related structures are well known for their noteworthy electronic and optical properties. The interaction between monovalent and trivalent atoms has a significant influence on their electronic as well as optical behavior. In the present work, a density functional theory based first-principles calculation is performed to investigate the structural, electronic, lattice dynamical, and optical properties of rhombohedral CuRhX2 (X = S, Se, Te) compounds. The electronic band structure of these compounds depicts semiconducting nature with an indirect bandgap of 1.8, 1.17, and 0.75 eV for CuRhS2, CuRhSe2, and CuRhTe2, respectively. There is a greater hole mobility and p-type conductivity in these compounds due to strong p-d hybridization. The phonon dispersion curves of these compounds confirm their dynamical stability as there is no imaginary frequency for any of the phonon modes in the entire Brillouin zone (BZ). Furthermore, we discuss mode compatibility at the zone center of the BZ and other high symmetry points of the BZ. The Raman spectra of CuRhX2 demonstrate two Raman active modes, namely, the Eg and A1g. The frequency of Raman active modes Eg and A1g decreases due to the increase in Rh-X bond length. The static dielectric constants fall in the range of 8.7-10.4. The absorption coefficient of these compounds is in the range of 1.5-2.0 eV depending upon the ionic radii of chalcogen atoms. Thus, it can be deduced that these systems can be efficiently used in solar energy converters in the UV as well as in the visible region.