Abstract
The magnetic structure, mechanical stability, and thermoelectric properties of quaternary VTiRhZ (Z = Si, Ge, Sn) Heusler alloys are investigated based on density functional theory (DFT). The calculations show that Y-type-I configuration is the most stable crystal structure for the studied alloys. The three alloys were found to have a half-metallic ferromagnetic structure with indirect band gaps in the majority spin channels of 0.42, 0.25, and 0.12 eV, for VTiRhSi, VTiRhGe, and VTiRhSn, respectively. They exhibit an appreciable total magnetic moment of 2 mu(B) and a perfect spin-polarization of 100%, which are promising for future spintronic applications. The Seebeck coefficient (S), electrical conductivity (sigma), and electronic thermal conductivity (kappa(e)) of VTiRhZ alloys were calculated using the semi-classical Boltzmann theory, whereas the lattice thermal conductivity (kappa(L)) was calculated using Slack's equation. The calculations predict n-type VTiRhSi and VTiRhGe with figure of merit (ZT) values of 1.13 and 0.62 at 800 K, respectively, whereas VTiRhSn exhibits a p-type with a ZT value of 0.92, which is promising for future thermoelectric applications.