[12a-PA2-1~77] 17 Nanocarbon Technology

▲ [12a-PA2-60] Clarification of Fe ordering in Fe_xTiS₂ structure using transmission electron microscopy

〇(D)Yi Ling Chiew¹, Masanobu Miyata¹, Mikio Koyano¹, Yoshifumi Oshima¹ (1.Japan Advanced Institute of Science and Technology)

Keywords:intercalated transition metal dichalcogenides, scanning transmission electron microscopy, transmission electron diffraction

Iron-intercalated titanium disulfide (Fe_xTiS₂) is a material where Fe guest atoms are introduced into the van der Waals gaps of TiS₂ nanosheets, thereby changing its atomic bonding and band structure, causing a deviation to its bulk properties. The physical properties of Fe_xTiS₂ were reported to be influenced by the distribution of Fe atoms in the van der Waals gap between TiS₂ layers. However, the in-plane and inter-plane orders of Fe atoms are still open to dispute. In this study, we managed to clarify the arrangements of Fe atoms in Fe_xTiS₂ crystals through scanning transmission electron microscope (STEM) and transmission electron diffraction (TED) observation three dimensionally from the orientations of [100], [110] and [001] and created full atomic models for Fe_xTiS₂ for x = 0.33 and 0.25. √3a x √3a x 2c superlattice for x = 0.33 and 2a x 2a x 2c superlattice for x = 0.25 were observed clearly. We also found that the low Fe concentration of x = 0.15 had dominant short range ordering of √3a.