Half-metallic ferrimagnetic characteristics of novel Ti₂-based ternary Heusler alloys: DFT calculations

Heusler alloys are predicted from a theoretical point of view to evolve into half-metals at room temperature (RT). Their three main assets are their suitable lattice matching irrespectively to the substrates, their high Curie temperature over RT, and the possibility to tune their intermetallic character for spin density of states at the Fermi energy level. The investigation of the magneto-electronic properties along with the structural, mechanical, and thermoelectric characteristics of a novel Ti₂-based ternary Heusler alloy Ti₂RuZ (Z = Si, Ge, Sn) family through the full-potential linearized augmented-plane-wave method (FP-LAPW) based on the Wien2k program is reported. The structural, magnetic, and electronic properties revealed that these compounds are ferrimagnet (FiM) materials. Due to the predicted and calculated negative formation energy, these investigated compounds could be thus synthesized experimentally. The mechanical study shows that these Ti₂-based ternary Heusler alloys are stable against any elastic deformation and belong to the brittle and stiff material category. The half-metallic ferrimagnet (HM-FiM) behavior was confirmed from the magneto-electronic calculations for all the investigated compounds. Furthermore, the thermoelectric responses as a function of chemical potentials and temperatures were analyzed and revealed that the new investigated alloys display a high figure of merit, a large Seebeck coefficient conjugated to low thermal conductivity. The present study proposes these compounds as potential candidates for spintronic thermoelectric devices.