Conduction Properties of Incommensurate Misfit Layer Compounds (CeS)_1.19(TiS_2)_n (n=1, 2)

Abstract

We investigated transport properties for incommensurate misfit layercompounds (CeS)_1.19(TiS₂)_n (n=1, 2) with stage-1 and stage-2structures. Both materials showed metallic conduction. The Hall effectshowed that the electrical conduction is dominated by the electroncarriers for both compounds, while thermoelectric power of stage-1(CeS)_1.19TiS₂ had a positive value of +5 μV/K at roomtemperature. This proved that the two different energy bands overlapat E_F of stage-1 (CeS)_1.19TiS₂. Detailed analysis of thethermoelectric power revealed the existence of short rangedomain-boundary phonon scattering process, where the mean free path isestimated to be of the order of 10 Å. This means that thelocal-lattice modulation induced by the incommensurate structure has aremarkable effect on the scattering process of the acoustic phonons aswell as the conduction electrons.