Electronicstructure of Zintl phase compounds of the Y3Au3Sb4type
P.Pécheur, L. Jodin, L. Chaput
Laboratoire de Physique desMatériaux, UMR7556, ENSMN, Parc de Saurupt, 54042 Nancy, France
Using an LMTO-TB method, we have obtained the electronic density ofstates for some Zintl phase compounds of the Y3Au3Sb4type containing only s, p and d electrons such as Zr3Ni3Sb4.These compounds are somewhat similar to half-Heusler compounds: theircomposition is close and the Zr and Ni have a similar (but distorted)neighborhood. They might be of interest for thermoelectric applications sincetheir thermal conductivity is lower.
Theelectronic structure is also rather similar to that of the half-Heuslercompounds. The partial densities of states clearly show an hybridizationbetween the d states of the two transition metals elements leading to a gapbetween bonding and antibonding d states. Each Sb atom introduces one s andthree p states below the gap, strongly hybridized with the d bonding states ofthe transition elements. This leads to the well known 18 s-p-d valenceelectrons count for filled valence bands (i.e. semiconducting behavior andmaximum stability) of the 1-1-1 half-Heusler compounds, and to a corresponding 62 s-p-d valence electrons count forthe Zintl 3-3-4 phases.
Sometentative calculations have been performed for hypothetical 62 compounds suchas Nb3Co3Sb4 which also shows a gap in itsdensity of states and Ti3Ni3Sb4which only has a minimum.