1999 Fiscal Year Final Research Report Summary
Electronic transport properties of surface-state bands on semiconductors
| Project/Area Number |
10650025
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
表面界面物性
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| Research Institution | The University of Tokyo |
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Principal Investigator |
HASEGAWA Shuji The Univ. Tokyo, Graduate School of Science, Associate prof., 大学院・理学系研究科, 助教授 (00228446)
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| Co-Investigator(Kenkyū-buntansha) |
NAGAO Tadaaki The Univ. Tokyo, Graduate School of Science, Research associate, 大学院・理学系研究科, 助手 (40267456)
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| Project Period (FY) |
1998 – 1999
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| Keywords | surface electronic transport / surface-state band / surface superstructure / semiconductor / two-dimensional electron system / RHEED / epitaxy / magneto resistance |
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| Research Abstract |
(1) We have developed an RHEED sample holder for surface conductivity measurements at low temperatures in ultrahigh vacuum, and installed it in a UHV-RHEED chamber with a superconducting magnet to measure Hall effect and magnetoresistance.
(2) Temperature dependence of surface conductivity of Si(111)-ィイD83ィエD8 X ィイD83ィエD8-Ag and ィイD821ィエD8 X ィイD821ィエD8-Ag surfaces was measured in a range of 40 to 300 K. In a temperature range of 100 to 300K, the conductivity of the ィイD821ィエD8 X ィイD821ィエD8 was the highest while that of the 7 X 7 was the lowest. The conductivity of the Ag-covered surfaces increased with temperature lowering, meaning a metallic conductivity. Below 100K, the 7 X 7 surface showed the highest conductivity.
(3) Magnetoresistance of Bi atomic layers on Si(111) surface was measured under a magnetic field up to 6 T at room temperature. The resistance changed by a few %.
(4) A ィイD83ィエD8 X ィイD83ィエD8 surface superstructure induced by 1/3 monolayer Sn adsorption on Si(111) surface was found to show a phase transition into a 3 X 3 phase by cooling down to around 100 K. This may be a charge-density wave transition, similar to that observed on Sn-covered Ge(111) surface.
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