| Project/Area Number |
13304025
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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 | The University of Tokyo |
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Principal Investigator |
IYE Yasuhiro The University of Tokyo, Institute for Solid State Physics, Professor, 物性研究所, 教授 (30125984)
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| Co-Investigator(Kenkyū-buntansha) |
ENDO Akira The University of Tokyo, Institute for Solid State Physics, Research Associate, 物性研究所, 助手 (20260515)
FUKUYAMA Hidetoshi Tohoku University, Institute for Materials Research, Professor, 金属材料研究所, 教授 (10004441)
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| Project Period (FY) |
2001 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥32,110,000 (Direct Cost: ¥24,700,000、Indirect Cost: ¥7,410,000)
Fiscal Year 2004: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
Fiscal Year 2003: ¥8,320,000 (Direct Cost: ¥6,400,000、Indirect Cost: ¥1,920,000)
Fiscal Year 2002: ¥8,840,000 (Direct Cost: ¥6,800,000、Indirect Cost: ¥2,040,000)
Fiscal Year 2001: ¥11,440,000 (Direct Cost: ¥8,800,000、Indirect Cost: ¥2,640,000)
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| Keywords | 2DEG / GaAs / lateral superlattice / magnetoresistance oscillation / antidot lattice / Aharonov-Bohm effect / Hofstadter butterfly / 磁気抵抗 / 磁性体 / 半導体複合構造 / AlGaAs / 変調構造 / 磁気輸送現象 / 量子ホール効果 / 磁場変調 / AB振動 / アンチドット / 二次元電子系 / ストライプ相 |
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| Research Abstract |
We carried out a systematic study of quantum oscillatory phenomena in triangular antidot lattices based on two-dimensional electron gas(2DEG) at semiconductor heterointerface. We have observed three different types of quantum interference effects, ---Altshuler-Aronov-Spivak(AAS) oscillation and Aharonov-Bohm(AB) type oscillation near zero field and another type of AB-type oscillation in the quantum Hall regime. We measured their temperature dependences, and elucidated the differences in the decoherence mechanisms. The gate bias dependence of the high field AB-type oscillation furnished information on the self-consistent screened potential formed around the antidots.
We studied electron transport under spatial gradient of magnetic field in 2DEG quantum wire decorated with mesoscopic ferromagnetic wire, and found (1)asymmetric conduction and rectifying effect, (2)universal conductance fluctuation in spatially varying magnetic field, and (3)magnetic barrier effect in the quantum Hall regim
… More
e.
We have uncovered a novel magnetoresistance oscillation in short period unidirectional lateral superlattices, which occurred in the lower magnetic field range than the so-called commensurability oscillations. From the analysis of its dependence on the electron density and modulation period, we concluded that the phenomenon is due to geometrical resonance of open orbits with the modulation period. The open orbits are created by Bragg reflection from the lateral superlattice, so this is a clear demonstration of the mini-gap formation. We have also established the method to quantify the modulation amplitude at the 2DEG plane from the analysis of the commensurability oscillation of magnetoresistance.
The Little-Parks oscillation of a superconducting wire network subjected to a spatially alternating magnetic flux pattern was investigated. The evolution of the oscillation pattern as a function of the amplitude of the alternation field and that of the uniform field was shown to agree well with the spectral edge of the corresponding Hofstadter butterflies. Less
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