Abstract
Using the Full Potential Linearized Augmented Plane Wave FP-LAPW, as
implemented in the Wien2k package. The structural, electronic, magnetic
and elastic properties of the Half Heusler (HH) RhNbGe and RhNbSn were
investigated. The Generalized Gradient Approximation (GGA) and the
Tran-Blaha-modified Becke-Johnson exchange potential method (TB-mBJ) was
applied to model the exchange correlation potential. Our results show
that the both compounds studied are mechanically stable. Moreover, RhNbZ
(Z:Ge,Sn) presents a semiconductor behavior obeying the Slater-Pauling
rule. The thermodynamic properties, in particular the Bulk modulus, the
heat capacity, the Debye temperature and the thermal expansion
coefficients of the two alloys are investigated using the quasi-harmonic
Debye model. The semi-classical Boltzmann theory, as implemented in the
BoltzTraP code, is used to study thermoelectric properties. The high
values obtained figures of merit ZT of RhNbGe and RhNbSn compounds make
them promising candidates for thermoelectric applications at low and
high temperatures.