Study of the Commensurate Superstructure in 4Hb–TaS2 by High Resolution Electron Microscopy

Abstract
The commensurate superstructures caused by CDW in 4Hb–TaS2 have been investigated by a high resolution electron microscope at room temperature. It was found that the two types of √13a × √13a superstructures, which rotated ±13.9° from a-axis in 00.1 plane, coexist in the same region, not in same layers but in different layers which have octahedral coordination. The two types of superstructure occur with different probabilities whose ratio depends on the samples. It was also observed that these superstructures were not greatly affected by dislocations in the crystal.