INTERLAYER INTERACTION IN MISFIT LAYER COMPOUNDS MTS3 (M = SN, PB, LA, T = TI, NB)

MTS3 (M = Sn, Pb, La; T = Ti, Nb), rigorously denoted by (MS)1 + x(TS2), are misfit layer compounds with nonstoichiometric compositions. We may regard them as intercalation derivatives of layered TS2 compounds, but also as materials having ultimately-thin one-dimensional superlattices with repeated distances of an atomic scale. The detailed investigation of interlayer interaction has been made, applying a difference technique to the sulfur K and niobium L2 X-ray absorption spectra. It is found that in all cases charge transfer occurs from MS to TS2 layers, but interlayer interaction depends on the combination of two kinds of alternately-stacked layers. PbNbS3 and SnNbS3 have stronger interlayer interaction than PbTiS3 and LaNbS3.