CONDUCTION PROPERTIES OF INCOMMENSURATE MISFIT LAYER COMPOUNDS (CES)(1.19)(TIS2)(N) (N=1,2)

We investigated transport properties for incommensurate misfit layer compounds (CeS)(1.19)(TiS2)(n) (n=1, 2) with stage-1 and stage-2 structures. Both materials showed metallic conduction. The Hall effect showed that the electrical conduction is dominated by the electron carriers for both compounds, while thermoelectric power of stage-1 (CeS)(1.19)TiS2 had a positive value of +5 mu V/K at room temperature. This proved that the two different energy bands overlap at E(F) of stage-1 (CeS)(1.19)TiS2. Detailed analysis of the thermoelectric power revealed the existence of short range domain-boundary phonon scattering process, where the mean free path is estimated to be of the order of 10 Angstrom. This means that the local-lattice modulation induced by the incommensurate structure has a remarkable effect on the scattering process of the acoustic phonons as well as the conduction electrons.