STM and STS studies of atomic structure and electronic states in quasicrystals
| Project/Area Number |
14550649
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical properties of metals
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| Research Institution | The University of Tokyo |
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Principal Investigator |
EDAGAWA Keiichi The University of Tokyo, Institute of Industrial Science, Associate Professor, 生産技術研究所, 助教授 (20223654)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 2003: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2002: ¥3,100,000 (Direct Cost: ¥3,100,000)
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| Keywords | quasicrystal / decagonal quasicrystal / scanning tunneling microscopy / tunneling spectroscopy / phason strain / 相変態 / STM / STS / 正10角形相 / フェイゾン / 電子状態 |
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| Research Abstract |
For the purpose of investigating atomic structure and electronic states In quasicrystals, we performed the following experiments. For a single-grained decagonal quasicrystal in the AL-Ni-Co system grown by Czochralski method, STM observations and tunneling spectroscopy were done. By STM the followings were observed: i)high perfection in the quasiperiodicity in the atomic arrangement, ii)10_5screw relation between the two kinds of quasiperiodic layers, iii)various periodicities in the atomic arrangement along the tenfold direction by surface reconstruction and iv) very low density of pason defects. In particular, the result iv) presents the first example of STM observation of any phason defect. By tunneling spectroscopy we found several peaks corresponding to surface states. In relation to the result iv), we investigated the phason relaxation process in quasicrystal by high-temperature in-situ HRTEM. The sample we used was an Al-Cu-Co decagonal quasicrystal. First, we introduced a uniform phason strai by 820℃ annealing. Then, we raised the temperature to 850℃ and observed the phason relaxation process. It was found that the phason relaxation proceeds with the shift of the boundary between the region with the uniform phason strain and the phason-free region. In this process the phason displacement in the region with the uniform phason strain remains unchanged and the tiling always continues coherently across the boundary.
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Report
(3 results)
Research Products
(25 results)
