Structural, electronic, elastic, thermoelectric and thermodynamic properties of the NbMSb half heusler (M¼Fe, Ru, Os) compounds with first principle calculations
The structural, electronic, elastic, thermoelectric and thermodynamic properties of NbMSb<br />
(M ¼ Fe, Ru, Os) half heusler compounds are reported. The full-potential linearized<br />
augmented plane wave (FP-LAPW) plus local orbital (lo) method, based on the density<br />
functional theory (DFT) was employed for the present study. The equilibrium lattice<br />
parameter results are in good compliance with the available experimental measurements.<br />
The electronic band structure and Boltzmann transport calculations indicated a narrow<br />
indirect energy band gap for the compound having electronic structure favorable for<br />
thermoelectric performance as well as with substantial thermopowers at temperature<br />
ranges from 300 K to 800 K. Furthermore, good potential for thermoelectric performance<br />
(thermopower S 500 meV) was found at higher temperature. In addition, the analysis of<br />
the charge density, partial and total densities of states (DOS) of three compounds<br />
demonstrate their semiconducting, ionic and covalent characters. Conversely, the calculated<br />
values of the Poisson's ratio and the B/G ratio indicate their ductile makeup. The<br />
thermal properties of the compounds were calculated by quasi-harmonic Debye model as<br />
implemented in the GIBBS code.
