Thermodynamic, thermoelectric and optoelectronic performances of Co2MB (M = Nb, Ta) full-heusler compounds for solar cell and UV absorber applications

Abstract

An investigation for estimating the thermodynamic, thermoelectric and optoelectronic performances of Co2MB (M = Nb, Ta) full-Heusler compounds is accomplished via density functional theory within full-potential linearized augmented plane wave (FP-LAPW) method. The generalized gradient approximation (GGA), GGA + U (Hubbard correction), Tran-Blaha modified Becke-Johnson potentials (TB-mBJ) and spin-orbit coupling (SOC) are utilized to handle the exchange and correlation potential. The electronic band structure of Co2NbB and Co2TaB confers half-metallic nature over reasonable band gaps; 0.71 and 1.11 eV, respectively within mBJ potential. The materials are manifested with the integer values of spin magnetic moment. Further, various thermodynamic parameters under the effect of temperature and pressure have been assessed. Interestingly, Co2NbB and Co2TaB exhibit fantastic thermoelectric performances concerning high figure of merit at 1200 K. Furthermore, the computed materials are optically active and display absorption spectra in visible and more significantly in UV region of incident light. Therefore, materials can be used as good UV absorbers.