First-principles investigation of structural, mechanical, electronic, and thermoelectric properties of Half-Heusler compounds RuVX (X = As, P, and Sb)

The structural, mechanical, electronic, and transport properties of RuVX (As, P, and Sb) Half-Heusler compounds are studied. The density functional theory (DFT) based on full-potential linearized augmented plane wave FP-LAPW method as integrated in the Wien2k code was used. The structural properties and mechanical parameters are carried out by mean of the generalized gradient approximation (GGA-PBEsol). The computed lattice parameters are in good accordance with the experimental data and other theoretical reports. In Addition, the elastic constants and the related elastic moduli indicate that RuVX (As, P, and Sb) compounds are ductile and mechanically stable in the cubic phase. The modified BeckeeJohnson potential (TB-mBJ) was applied to enhance the calculation of the electronic properties. It is found that the RuVX (As, P, and Sb) compounds are semiconductors with an indirect band-gap. GGA + U calculations are performed to investigate the relationship between band gap and Hubbard potential. Studies of thermoelectric properties were performed by the Boltzmann transport equations as incorporated in BoltzTraP code. At room temperature, the obtained values of the figure of merit (ZT) for RuVAs, RuVP, and RuVSb compounds are around unity, which confirm that all compounds have good transport efficiency and can be utilized for electricity production and thermoelectric devices. (C) 2018 Elsevier B.V. All rights reserved.