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.