1995 Fiscal Year Final Research Report Summary
Electronic States in Two-dimensional Quasicrystals
| Project/Area Number |
06452054
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | Institute for Solid State Physics, Univ.of Tokyo |
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Principal Investigator |
TAKEUCHI Shin Univ.of Tokyo, Institute for Solid State Physics, Professor, 物性研究所, 教授 (60013512)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Kunio Univ.of Tokyo, Institute for Solid State Physics, Research Associate, 物性研究所, 助手 (50107439)
EDAGAWA Keiichi Univ.of Tokyo, Institute of Industrial Science, Lecturer, 生産技術研究所, 講師 (20223654)
MAEDA Koji Univ.of Tokyo, Dept.Appl.Phys., Prof., 工学部, 教授 (10107443)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Quasicrystal / Decagonal Phase / Electronic States / Scanning Tunneling Microscopy / Electron Localization |
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| Research Abstract |
1.High-order approximant crystals of decagonal phase with lattice constants of a few nm have been produced for Al-Pd-Fe and Al-Co systems. The resistivity along the c-axis of these approximant crystals shows a metallic behavior, while the resistivity in the pseudo-quasicrystalline plane is an order higher than that along the c-axis and exhibits very small temperature dependence. These results are essentially the same as those of decagonal quasicrystals previously obtained, and are consistent with the theoretical results obtained by Fujiwara et al.in whihc the high resistivity in the (pseudo-) quasicrystalline plane is attributed to a very large effective mass of electrons as a result of localization of wavefunctions in atomic cluster columns along the c-axis.
2.Scanning tunneling microscopy (STM) observation has been made for single crystals of an Al-Co-Ni decagonal quasicrystals produced by slow solidification from the melt. Observation has been made for tenfold-symmetric plane of the decagonal quasicrystal after Ar-ion sputtering and anealing. STM image has been obtained with a bias voltage of -0.1V and a set-current of 1nA.STM images often showed an irregular mottled pattern with a wavelength of a few nm. The pattern is quite similar to that of spatial distribution of the amplitude of the wavefunction of elctrons near the Fermi-level theoreticaly calculated by Fujiwara et al.and hence the observed pattern is considered to reflect the spatial localization of electrons.
Thus, the special electronic states in two-dimensional quasicrystals have been experimentally clarified to a large extent.
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