| Project/Area Number |
60460025
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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
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
TAKAHASHI Takashi (1986) Department of Physics, Tohoku University, 理学部, 助手 (00142919)
佐川 敬 東北大学, 理学部, 教授
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| Co-Investigator(Kenkyū-buntansha) |
KONO Shozo Department of Physics, Tohoku University, 理学部, 助教授 (60133930)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥7,500,000 (Direct Cost: ¥7,500,000)
Fiscal Year 1986: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1985: ¥6,800,000 (Direct Cost: ¥6,800,000)
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| Keywords | photoemission / inverse photoemission / low temperature / UPS / BIS / graphite / 超伝導体 |
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| Research Abstract |
We have constructed a spectrometer for photoemission and inverse photoemission spectroscopies to study the electronic structures of solids and solid surfaces at low temperature. With this spectrometer, we have performed photoemission and inverse photoemission measurements for several interesting materials. The results obtained are; (1) We have successfully determined the band structure of the first-stage-alkali-metal-graphite intercalation compounds (AGICs) for the first time by keeping the sample at low temperature. The long-standing controversy on the charge-transfer in AGICs has been terminated. It was found that the s electron of an alkali atom is transfered to and shared by the <alpha^*> band and the interlayer band with an almost equal weight. (2) We could map out the unoccupied electronic structure of graphite by angle-resolved inverse photoemission spectroscopy. This is the first step to proceed to the low temperature inverse photoemission study of AGICs. It was found that the interlayer band which plays an important role in charge-transfer in AGICs is located about 3.5 eV above the Fermi level at the <GAMMA> point. (3) In order to study the mechanism of the high-Tc superconductivity, we have performed a low temperature photoemission measurement for La- and Y-superconconductors. The results show that an intra-atomic Coulomb energy between d electrons is very large in these superconductors. It is concluded that this strong d electron correlation dominates the electronic structure and plays a key role for the appearence of the high-Tc superconductivity.
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