| Project/Area Number |
11440102
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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 | Keio University |
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Principal Investigator |
SHIRAHAMA Keiya Keio University, Physics, Associate Professor, 理工学部, 助教授 (70251486)
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| Co-Investigator(Kenkyū-buntansha) |
SHIBAYAMA Yoshiyuki Keio University, Physics, Research Associate, 理工学部, 助手 (20327688)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥16,100,000 (Direct Cost: ¥16,100,000)
Fiscal Year 2001: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2000: ¥4,900,000 (Direct Cost: ¥4,900,000)
Fiscal Year 1999: ¥9,200,000 (Direct Cost: ¥9,200,000)
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| Keywords | Wigner Crystal / Two-Dimensional Electron System / Nonlinear Conduction / Liquid Helium / 非線型伝導 |
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| Research Abstract |
In this research project, we studied the dynamics of the Wigner crystal phase of two-dimensional electrons trapped on free surfaces of liquid helium. In order to elucidate the mechanisms of nonlinear transport phenomena including (1) the conductivity jump, and (2) proportionality of the longitudinal conductivity to the driving voltage, under a perpendicular magnetic field, and (3) the non-Ohmic conduction on a liquid ^3He surface, we have conducted experiments to make a real-time observation of the nonlinear crystal dynamics
We have developed a new experimental method, using a "t^2" voltage pulse, whose leading and trailing edges change in proportion to the square of time. This pulse gives a continuous sweep of the driving force applied to the crystal. The observed response clearly shows the sliding behavior, revealing that the external force to the crystal determines the sliding transition.
In addition to the above experiments, we have studied the electrons on the free surface of ^3He-^4He liquid solutions. It offers us a clue to elucidate the effect of the underlying liquid properties(^3He or ^4He) to the dynamics of the Wigner crystal. We have made a conductivity measurement of the electrons trapped on the liquid mixture surfaces with various ^3He concentrations. However, we have observed anomalous resonance phenomena under a magnetic field. The characteristics of the resonance are similar to the properties of so-called edge magnetoplasmons, in which the plasma oscillation propagates around the perimeter of the electron sheet. Further studies of this unexpected resonance are underway.
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