Redox competition and stability:: rare earth misfit layer compounds as an example

Recent studies of the electronic structure of the rare earth misfit layer compounds (LnS)(1+x)TS2 (Ln = rare earth, T = Ti, V, Cr, Nb, Ta) allow one to present a model which explains their stability. Two redox competitions, one between the [LnS] and the [TS2] slabs, and the second between the T nd and S 3p bands, are found to govern the stabilization of these compounds. This study shows how the modification of the electronic structure of each slab, by moving along the rare earth or the transition elements, defines a narrow stability range for the misfit layer structure. (C) 1999 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.