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C-13 NMR study on the charge-ordering salt α'-(BEDT-TTF)2IBr2
| Title: | C-13 NMR study on the charge-ordering salt α'-(BEDT-TTF)2IBr2 |
| Authors: | Hirose, Shinji Browse this author | | Kawamoto, Atsushi Browse this author |
| Keywords: | charge-ordered states | | hyperfine interactions | | nuclear magnetic resonance | | organic superconductors | | paramagnetism | | superconducting transitions |
| Issue Date: | Oct-2009 |
| Publisher: | American Physical Society |
| Journal Title: | Physical Review B |
| Volume: | 80 |
| Issue: | 16 |
| Start Page: | 165103 |
| Publisher DOI: | 10.1103/PhysRevB.80.165103 |
| Abstract: | Among quasi-two-dimensional organic conductors, (BEDT-TTF)2X, what form the two column structure of α or θ is thought to show a charge-ordering insulating state. The α' modification is the other candidate for a charge-ordering state. To determine the existence of a charge-ordering state and electron magnetism in the α' phase, which has a symmetry that differs from that of the α and θ phases, we utilized C-13-NMR to examine α'-(BEDT-TTF)2IBr2 in which one side of the central carbon on the BEDT-TTF molecule is substituted with C-13 nuclei. We observed changes in its spectrum at 200 K. The angular dependence of the NMR shift at 15 K indicated that the charge-ordering pattern is intracolumn disproportionation and the ratio of charge disproportionation on the spin-poor site and spin-rich sites is almost 1:0. The angle dependence of NMR spectrum at 60 K suggests that the hyperfine coupling tensor in the paramagnetic charge-ordering state is determined not only by the charge density of on-site molecules but also by the contribution of off-site molecules. The change in hyperfine coupling tensor must be taken into account in NMR studies of the paramagnetic CO state. |
| Rights: | © 2009 The American Physical Society |
| Type: | article |
| URI: | http://hdl.handle.net/2115/39842 |
| Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 河本 充司
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