Abstract
A natural superlattice was built by intercalating a SnS layer into the van der Waals gap of layered TiS2, as has been observed by HRTEM. In the in-plane direction, the thermoelectric performance was found to be much improved, because the electron mobility was maintained while the phonon transport was suppressed, which was identified due to softening of transverse sound velocity because of weak interlayer bonding. It is also found that in the cross-plane direction, the thermal conductivity is even lower than the predicted minimum thermal conductivity and the random transverse displacement of the SnS layers in the direction parallel to the layers possibly accounts for it.
