| Project/Area Number |
11304019
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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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Ⅰ(光物性・半導体・誘電体)
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| Research Institution | Tohoku University |
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Principal Investigator |
SAWADA Anju Tohoku University, Graduate School of Science, Physics Department, Associate Professor, 大学院・理学研究科, 助教授 (90115577)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Katsuhiko Miyagi National College of Technology, Department of General Science, Professor, 総合科学系, 教授 (80187715)
OHNO Yuzo Tohoku University, Research Institute of Electrical Communication, Associate Professor, 電気通信研究所, 助教授 (00282012)
EZAWA Jyunichi Tohoku University, Graduate School of Science, Physics Department, Professor, 大学院・理学研究科, 教授 (90133925)
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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 |
¥34,800,000 (Direct Cost: ¥33,900,000、Indirect Cost: ¥900,000)
Fiscal Year 2001: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2000: ¥11,500,000 (Direct Cost: ¥11,500,000)
Fiscal Year 1999: ¥19,400,000 (Direct Cost: ¥19,400,000)
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| Keywords | Quantum Hall effect / Composite Boson / Activation energy / Interlayer coherence / Bose condensation / Gallium Arsenide / Pseudospin / Spin / 擬スピン / ホールプラトー / スカーミオン |
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| Research Abstract |
Skyrmion excitations were measured and compared for the first time in the bilayer quantum Hall (QH) state at the Landau-level filling factor ν=2 and in the monolayer QH state at ν=1. The observed number of flipped spins, Ns, is 14 in the bilayer sample with a large tunneling gap, and Ns=7 in the bilayer sample with a small tunneling gap, while it is Ns=7 in the monolayer sample. The difference is interpreted to be due to the interlayer exchange interaction.
In the next stage, we measured the magnetoresistance of bilayer QH effects at the fractional filling factor ν=2/3 by changing the total electron density and the density difference between two layers. Three different QH states were separated by two types of phase transition : One is the spin transition and the other is the pseudospin transition. In addition, two different hystereses were detected, one of which is specific to bilayer systems. The phase transitions and the hystereses are described well by a composite fermion model extended to a bilayer system.
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