Optical and thermal properties of the half-Heusler VFeSb and NbFeSb alloys

Abstract

In this work, we used the First-principles method Fplapw based on density functional theory (DFT) to study the thermal and optical properties of Half-Heusler compounds VFeSb and NbFeSb. These materials are characterized with a small and narrow band gap semiconductors close to the fermi level; following the electron number and other structural properties of these materials have a high performance thermoelectric .In our calculations, we will use the structural and electronic properties for our materials already calculated in previous publications. The modified Becke–Johnson exchange potential (mBJ)-LDA approach was also used. Optical properties such as complex dielectric function, refractive index, reflectivity, energy loss function for incident photon energy up to 30eV have been predicted. We also analyze the influence of the pressure and temperature on the primitive cell volume, heat capacity, volume expansion coefficient, and Debye temperature of the Half-Heusler compounds.