2001 Fiscal Year Final Research Report Summary
Construction of ultrahigh-resolution photoemission spectrometer with small spot size using laser as a photon source
| Project/Area Number |
12440098
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SHIN Shik The University of Tokyo, Institute for Solid State Physics, Professor, 物性研究所, 教授 (00162785)
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| Co-Investigator(Kenkyū-buntansha) |
YOKOYA Takayoshi The University of Tokyo, Institute for Solid State Physics, Research Associate, 物性研究所, 助手 (90311646)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Soft x-ray laser / ultrahigh-resolutioin PES / PES with small spot size / low-Te superconductor / superconducting gap / anisotropic superconductivity |
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| Research Abstract |
We have constructed a low-temperature and high-resolution photoemission (PE) spectrometer for using a laser as a photon source. We have achieved an energy resolution of 0.8 meV without an energy width of light\ an angular resolution of 0.2 degree, and the lowest sample temperature of 4 K, which are the highest performance of PE spectrometer in the world.
Using this spectrometer, we have studied superconductors with a low transition temperature (low-Tc). We have observed a superconducting gap of elemental metals (Nb and Pb) as well as phonon-induced fine structures in Pb. We have concluded anisotropic s-wave superconductivity for Yni_2B_2C from an impurity-induced change in gap anisotropy. We have provided a spectroscopic evidence for a multiple gap of MgB_2. We have measured an isotropic s-wave gap and a normal-state pseudogap in Ba_<1-x>K_xBiO_3. We have observed the superconducting gap of Ba_8Si_<46> and classified it as a weak coupling superconductor. From angle-resolved study of 2H-NbSe_2, we have resolved all the Fermi surface sheets predicted by band structure calculations and have observed FS sheet dependent superconductivity.
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