The half metallic feature at high temperature of the novel half-Heusler alloys and their [100] oriented layered superlattices: A DFT investigations

Abstract

Herein, we have investigated by means of the DFT calculations the magneto-electronic properties and thermoelectric responses of the novel half-Heusler NbFe(Mn)Sn compounds and their layered superlattices growing along [100] direction. The ground-state properties and magnetic stability revealed that the bulk compounds were ferromagnetic materials. The formation energy was determined meticulously and revealed that the studied materials could be synthesized experimentally. The half-metallic ferromagnetism with the presence of the strong p-d hybridization have been strongly confirmed from the magneto-electronic calculations for all the studied materials. The Curie temperature was estimated from the mean field approach, the obtained values exceed the ambient temperature. Furthermore, the thermoelectric response was evaluated and categorized the investigated compounds as a good thermoelectric materials due to the high figure of merit, large Seebeck coefficient and low electronic part of thermal conductivity. The curve of spin polarization (SP) as a function of temperature divulged that the 100% SP was conserved at high temperature for NbFeSn and superlattice materials. The phonon dispersion was calculated in order to examine the dynamic stabilities of the studied materials. The present detailed study made these materials as a potential candidates for spintronic thermoelectric devices.