| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1989: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1988: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
In order to carry out an angle-resolved ultraviolet photoemission spectroscopy (ARUPS) research into the electronic band structures of clean and gas-adsorbed transition-metal single-crystal surfaces and of single-crystal oxides, we made a computer-controlled data-acquisition system the first thing. After that, we performed ARUPS studies on single-crystal high-T_c oxides, YBa_2Cu_3O_<7-x> (001) and Nd_<2-x>Ce_xCu O_4 (001), and on clean and gas-adsorbed Fe(110) surfaces, and we have obtained the following new results:
1. APUPS of epitaxially grown YBa_2Cu_3O_<7-x> (001) single-crystal thin films, exhibiting sharp (1X1) LEED patterns, reveals a clear Fermi edge and fine structures near the edge. Some of the valence-band photoemission features show k-space dispersion. These results suggest that the electronic structure of this oxide can be treated within the framework of the one-electron band picture.
2. ARUPS of epitaxially grown Nd_<2-x>Ce_xCuO_4(001) single-crystal thin films, exhibiting sharp (1X1) LEM patterns, reveals a resolution-limited Fermi edge and small k-space dispersion (0.2-0.4 eV) of the valence bands. The ARUPS spectra can be compared to the band calculation to a fair degree. A bandlike state of dominant Cu 3d character is found just below the Fermi level. This state may be a Kondo-type renormalized heavy-electron band.
3 . ARUPS of Fe(110) reveals spin-orbit splitting of the upper 3d band into two components separated by -110 meV, being much larger than theoretical estimate (-45 meV).
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