Nanotubes from the Misfit Layered Compound (SmS)1.19TaS2: Atomic Structure, Charge Transfer, and Electrical Properties
Creators
- 1. Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
- 2. CEITEC – Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00 Brno, Czech Republic
- 3. Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- 4. Department of Chemical Research Support, Weizmann Institute, Rehovot 7610001, Israel
- 5. Ames Laboratory, U.S. Department of Energy, Ames, IA, 50011-3020, USA
- 6. 7Department of Physics, SUNY Buffalo State, Buffalo, New York 14222, USA
- 7. Institute of Solid State Chemistry UB RAS, 620990 Ekaterinburg, Russian Federation
Description
Misfit layered compounds MX-TX2, where M, T= metal atoms; X = S, Se or Te, (MLC) and their nanotubes are of significant interest due to their rich chemistry and unique quasi-1D structure. In particular, Ln-TX2 (Ln= rare-earth atom) constitute a relatively large family of MLC, from which nanotubes have been synthesized. The properties of MLCs can be tuned by the chemical and structural interplay between LnX and TX2 sub-layers and alloying of each of the Ln, T and X elements. In order to engineer them to gain desirable performance, a detailed understanding of their complex structure is indispensable. MLC nanotubes are a relatively new-comer and offer new opportunities. In particular, like WS2 nanotubes before, the confinement of the free-carriers in these quasi-1D nanostructures and their chiral nature offer intriguing physical behavior. Highresolution transmission electron microscopy in conjunction with a focused ion beam are engaged to study SmS-TaS2 nanotubes and their cross-sections at the atomic scale. The atomic resolution images distinctly reveal that Ta is in trigonal prismatic coordination with S atoms in a hexagonal structure. Furthermore, the position of the sulfur atoms in both the SmS and the TaS2 sub-lattices, is revealed. X-ray photoelectron spectroscopy, electron-energy loss spectroscopy and X-ray absorption spectroscopy are carried out. These analyses conclude that charge transfer from the Sm to the Ta atoms leads to filling of the Ta 5dz 2 level, which is confirmed by density functional theory (DFT) calculations. Transport measurements show that the nanotubes are semimetallic with resistivities in the range of 10-4 Ω⸳cm at room temperature and magnetic susceptibility measurements show a superconducting transition at 4 K.
Notes
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Kolíbal_Tenne_ChemMat_preprint.pdf
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