1994 Fiscal Year Final Research Report Summary
Adsorption on active surfaces studied by the combined methods of STM and surface XAFS
| Project/Area Number |
05403010
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
機能・物性・材料
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| Research Institution | The University of Tokyo |
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Principal Investigator |
OHTA Toshiaki The Univ.Tokyo, Graduate School of Science, Professor, 大学院・理学系研究科, 教授 (80011675)
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| Co-Investigator(Kenkyū-buntansha) |
ASAKURA Kiyotaka The Univ.Tokyo, Fac.Science, Associate Professor, 理学部, 助教授 (60175164)
NAMBA Hidetoshi The Univ.Tokyo, Fac.Science, Assistant, 理学部, 助手 (40118766)
KITAJIMA Yoshinori KEK,PF,Assistant, 放射光実験施設, 助手 (00204892)
YOKOYAMA Toshihiko The Univ.Tokyo, Graduate School of Science, Lecturer, 大学院理学系研究科, 講師 (20200917)
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| Project Period (FY) |
1993 – 1994
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| Keywords | STM / Surface XAFS / Surface Reconstruction / Adsorption of Atoms |
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| Research Abstract |
An ultrahigh vacuum chamber for surface analysis including a STM instrument was exploited. LEED and Auger electron spectra can be measured using a reverse-view four-grid LEED optics. X-ray photoelectron spectra are also obtainable employing a Mg and Al twin-anode X-ray tube and a concenric hemispherical electron energy analyzer. We have examined a performance of the system and successfully obtained good STM images of (5ROO<3>*2) -rect. S/Ni (111), the quality of which is comparable to the previously reported data. Next we have investigated surface structure of (ROO<17>*ROO<17>) R14ﾟS/Cu (100) by means of STM and S K-edge SEXAFS.The combined methods of STM and SEXAFS are quite useful for the determination of surface structure, since STM gives information on the locations of adsorbate atoms as well as a long-range structure, while SEXAFS clarifies relative locations between adsorbate and substrate, these information being fully complementary to each other. On (ROO<17>*ROO<17>) R14ﾟS/Cu (100) STM has revealed the lateral positions of two kinds of S atoms. Combining the results of SEXAFS, we have proposed a new surface structure model in which the surface Cu layr is significantly reconstructed. In the unit cell four S atoms locate on the rearranged hollow site of the surface Cu layr and other four embedded S atoms are on the normal fourfold hollow site of the second Cu layr.
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