Abstract
Summary
Direct energy bandgap materials are crucial for efficient optoelectronics devices. Therefore, investigating new direct gap materials is important. In the present work, two novel d‐metal sulfides Sc2CdS4 and Y2CdS4 compounds are investigated by using the all‐electron full‐potential linearized augmented plane‐wave method. The energy optimization predicts lattice constants 10.85 and 11.31 Ǻ for Sc2CdS4 and Y2CdS4, respectively. Both the compounds show semiconducting nature and direct bandgap with a value of 1.886 eV for Sc2CdS4 and 2.209 eV for Y2CdS4. Strong hybridization between S‐p and Sc/Y‐d orbitals is present among valence and conduction bands, which is beneficial to electrical transport. Key optical parameters are calculated. The static value of the reflectivity R(0) and refractive index n(0) varies inversely with the energy bandgap (Eg). Both the compounds Sc2CdS4 and Y2CdS4 are P‐type thermoelectric materials because the holes carriers dominate the electronic transport. Both the compounds reveal figure of merit of about 0.5. Appropriate direct energy gap and figure of merit indicate the possible applications of these compounds for energy conversion devices.