Isolated and condensed M2Co2 clusters (M = Nb, Ta) in the layered tellurides Nb2Co2Te4 and TaCo2Te2

Abstract

The new ternary layer compounds Nb₂Co₂Te₄ and TaCo₂Te₂ have been prepared by reaction of the elements at high temperature; isolated and condensed M₂Co₂(M = Nb or Ta) clusters are the structural key features of these unusual layer compounds, tight-binding band structure calculations indicate the importance of Nb–Co(Ta–Co) and Nb–Nb(Ta–Ta) interactions for the electronic stability of the structures.