Effect of vacancies on the electronic structure of Pd_xTiSn alloys

Abstract

We have studied the influence of vacancies on the electronic structure of PdxTiSn (1⩽x⩽2) Heusler-type alloys by the ab initio tight binding linearized muffin-tin orbital (TB LMTO) method. The LMTO calculations have shown that PdTiSn can be classified as a narrow gap semiconductor with the gap equal to 0.4 eV. The gap vanishes for x>1.125. The calculations have shown that the local chemical disorder in PdTiSn depresses the gap. The lattice parameter obtained from the minimum of the total energy is constant for 1.5⩽x⩽2 and for x<1.5 its value decreases.

Disorder and Itinerant Magnetism in Full Heusler Pd2TiIn

“…For example, Pd vacancies were proposed as a way of modifying the band structure of Pd 2 TiSn, with compositions intermediate between the full Heusler and the half-Heusler PdTiSn. [64] We considered vacancies on each of the three sites, using the same supercell method as for the antisite pairs discussed above. Vacancy formation energies were calculated with respect to bulk Pd, Ti and In metal in their experimental crystal structures, specifically fcc Pd, hcp Ti and body centered tetragonal In.…”

Onset of itinerant ferromagnetism associated with semiconductor-metal transition in Ti x Nb1 − x CoSn half Heusler solid solution compounds

“…These phases crystallize in the C1 b structure (space group F43m) and may be considered as a prototype class of compounds for addressing a variety of general issues relating magnetic and electronic properties of solids. Due to the vacant site, the overlap between the transition metal wave functions is smaller, which gives rise to the formation of a narrow gap near the Fermi level and these compounds exhibit halfmetallic or semiconducting behaviour [1,3,5,[14][15][16][17][18].…”