A LEED and photoemission spectroscopy study of the surface of the incommensurate misfit layer compound (SnS)1.16TaS2

The misfit layer compounds with stoichiometry (MX)1+δTX2 are composites of MX and TX2 layers, which are stacked alternatingly. This type of compound is known for M = Sn, Pb, Bi, La; T = Ti, Ta, Nb and X = S, Se. The MX layers adopt an SnS-type crystal structure. The compounds are synthesized at high temperature. Therefore the stability gained by the alternation of the stacking of the TX2 layers by MX layers must be considerable. LEED photographs and angular resolved UPS spectra are presented to show the large differences between the commensurate and the incommensurate directions in (SnS)1.16TaS2. Core level photoemission spectra indicate that there is no charge transfer from one layer to the other. Thus the stability of (SnS)1.16TaS2 cannot be explained by charge transfer.