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2004 Fiscal Year Final Research Report Summary

Quantum Transport in Two-Dimensional Electron Systems in Super Periodic Structures

Research Project

Project/Area Number 13304025
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section一般
Research Field 固体物性Ⅰ(光物性・半導体・誘電体)
Research InstitutionThe University of Tokyo

Principal Investigator

IYE Yasuhiro  The University of Tokyo, Institute for Solid State Physics, Professor, 物性研究所, 教授 (30125984)

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)
Project Period (FY) 2001 – 2004
Keywords2DEG / GaAs / lateral superlattice / magnetoresistance oscillation / antidot lattice / Aharonov-Bohm effect / Hofstadter butterfly
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

  • Research Products

    (7 results)

All 2005 2004

All Journal Article (7 results)

  • [Journal Article] New Class of Small Amplitude Low-Field Magnetoresistance Oscillation in Unidirectional Lateral Superlattice : Geometric Resonance of Bragg-Reflected Cyclotron Orbit2005

    • Author(s)
      A.Endo, Y.Iye
    • Journal Title

      Phys.Rev.B 71

      Pages: 081303-1-081303-4

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Dependence of Modulation Amplitude on Electron Density in Unidirectional Superlattice : The Effect of Thickness of the Two-Dimensional Electron Gas2005

    • Author(s)
      A.Endo, Y.Iye
    • Journal Title

      J.Phys.Soc.Jpn. 74(印刷中)

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Dependence of Modulation Amplitude on Electron Density in Unidirectional Superlattice : The Effect of Thickness of the Two-Dimensional Electron Gas2005

    • Author(s)
      A.Endo, Y.Iye
    • Journal Title

      J.Phys.Soc.Jpn. 74(in press)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Aharonov-Bohm type Effects in Triangular Antidot Lattices2004

    • Author(s)
      Y.Iye, M.Ueki, A.Endo, S.Katsumoto
    • Journal Title

      J.Phys.Soc.Jpn. 73

      Pages: 3370-3377

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Hofstadter Butterflies in Modulated Magnetic Field---Superconducting Wire Network with Magnetic Decoration2004

    • Author(s)
      Y.Iye, E.Kuramochi, M.Hara, A.Endo, S.Katsumoto
    • Journal Title

      Phys.Rev.B 70

      Pages: 144524-1-144524-9

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Universal Conductance Fluctuations in a Narrow Channel of Two-Dimensional Electron Gas under Gradient Magnetic Field with Zero Mean2004

    • Author(s)
      M.Hara, A.Endo, S.Katsumoto, Y.Iye
    • Journal Title

      J.Phys.Soc.Jpn. 73

      Pages: 2928-2931

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Transport in a Two-Dimensional Electron-Gas Narrow Channel with a Magnetic-Field Gradient2004

    • Author(s)
      M.Hara, A.Endo, S.Katsumoto, Y.Iye
    • Journal Title

      Phys.Rev.B 69

      Pages: 153304-1-153304-4

    • Description
      「研究成果報告書概要(和文)」より

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Published: 2006-07-11  

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