Properties of the double half-heusler alloy ScNbNi2Sn2 with respect to structural, electronic, optical, and thermoelectric aspects

Abstract

In the current work, the structural, electronic, thermoelectrics, and optical characteristics of the double half Heusler (DHH) ScNbNi2Sn2 compound are reported for the first time using density functional theory (DFT). The computed band structures show typical semiconductor behavior with an indirect bandgap (0.47 eV) using EV-GGA approximation. We also investigated the optical properties such as the dielectric function, optical conductivity, refractive index. Boltzmann's semiclassical theory attempts to explain a simulation concept in the BoltzTrap software, and the findings were presented and analyzed in terms of electrical conductivity, electronic and lattice thermal conductivities, the Seebeck coefficient, and the Figure of merit over a 50 K–1000 K temperature range. At room temperature, with a low magnitude of lattice thermal conductivity (κL) (5.30776 W/m. K) and a maximum value of the merit factor (ZT) is 0.64 at 900 K for ScNbNi2Sn2 compound is observed. These findings suggest that our material may be a viable option for use in high-temperature thermoelectric devices. We calculated (S, (σ/τ), (ke/τ)) along the x, y, and z axes utilizing the EV-GGA method. We found out that our compound is thermoelectrically anisotropic. We have also studied in EV-GGA the effect of the carrier concentration on the Seebeck coefficnet at T = 600 K. The maximum value of S is 356.9905 μV/K with n=3.04×1019Cm−3 within GGA and EV-GGA respectively.