First-principles calculations to investigate structural, elastic, electronic and thermoelectric properties of narrow-band gap half-Heusler RhVX (X = Si, Ge) compounds

This research work aims to understand the structural, electronic, elastic and thermoelectric properties of half-Heusler RhVX (X = Si, Ge) compounds. The included properties are explored by using the full-potential linearized augmented plane wave method under the support of density functional theory by employing Wien2k computational code. Within the calculations, the lattice constant of RhVSi is found as 5.69 Å and for RhVGe as 5.74 Å. These values are in admirable agreement with the existing literature. Further, both the half-Heusler compounds are explored as ductile in ground state from the calculation of elastic and mechanical properties. The narrow indirect bandgap (0.21 eV for RhVSi and 0.33 eV for RhVGe) semiconductor character of both the RhVX compounds is revealed from the results of electronic properties. The thermoelectric performance of RhVX compounds is analyzed by calculating the important parameters such as thermal conductivity (both electronic and lattice), Seebeck coefficients, carrier concentration and figure of merit. Both the RhVX compounds are suggested as suitable candidates for thermoelectric power generators at high temperatures.