Assessing half-Heusler alloys PtNbZ (Z=Al, Ga, In) via DFT: acceptability for thermoelectric applications

Abstract

The current study relies on the investigation of PtNbZ (Z = Al, Ga, In) half-Heusler alloys using two distinct methods: the generalized gradient approximation (GGA) and a modified version of the Beck–Johnson potential. The structural parameters and ground state are obtained by optimizing the alloys in various structural phases using the GGA technique, and the findings show that the alloys crystallize in the Y₁ phase with non-magnetic spin ordering. With zero net magnetic moments, these alloys perfectly follow the Slater–Pauling rule M_T = Z_T-18. The elastic parameters determine the structural stability and anisotropic character of the medium. For varied direction-dependent sound velocities, the alloys investigated are ductile, with the Debye temperatures being 423.53, 451.66 K, and 392.97 K, respectively. The alloys possess high figure of merit (ZT) values of 0.59, 0.76 and 0.78, respectively, suggesting their applications in thermoelectric power generation.