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Research on the Ground State and Transport Properties of Dipole-Type Quantum Hall States

Research Project

Project/Area Number 18540311
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Condensed matter physics I
Research InstitutionThe University of Tokyo

Principal Investigator

YOSHIOKA Daijiro  The University of Tokyo, Graduate School of Arts and Sciences, Professor (30114713)

Project Period (FY) 2006 – 2007
Project Status Completed (Fiscal Year 2007)
Budget Amount *help
¥1,940,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥240,000)
Fiscal Year 2007: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2006: ¥900,000 (Direct Cost: ¥900,000)
KeywordsQuantum Hall Effect / Two-dimensional electron system / Strong magnetic field / Exciton / Bose condensation / Dipole / 強相関電子系 / 半導体物性
Research Abstract

It has been known that the dipole-type quantum Hall states are realized in the following two situations,(i) single layer system at Landau level filling factor 1/2, and(ii) bilayer system at total filling 1. In the present investigation We investigated these situations, and furthermore, We found that there are other situations in which the dipole-type correlation is realized. We obtained the following results.
1. We have found by DMRG (density matrix renormalization group) technique that the dipolar correlation continuously changes from intralayer correlation to interlayer correlation as the distance between the bilayer is decreased. We tries to describe these continuous transition by a mean field theory to understand the transport properties. Because of a minor problem which is not satisfactorily solved, this investigation has not been published, but We have obtained several results, and hoping to be able to publish in near future.
2. Around a positive impurity, dipolar bound states are formed. The charge distribution depends on the binding energy, and this behavior is observed by STS (scanning tunneling spectroscopy). We have calculated wave function, binding energy and local density of states for two systems, one with ordinary parabolic dispersion and the other with linear dispersion realized in graphene. We clarified the difference due to the difference in dispersion, and obtained reasonable agreement with experiment.
3. For bilayer systems with different density so that the Fermi level is at different Landau levels in the two layers, dipolar correlation developes and new kind of ground state becomes possible in wider filling factors. Until now we obtained only qualitative results. To obtain quantitaitve results, mean field analysis is underway. Once we obtained the results we proceed to DMRG calculation. The results by the mean field analysis will be published in near future.

Report

(3 results)
  • 2007 Annual Research Report   Final Research Report Summary
  • 2006 Annual Research Report
  • Research Products

    (7 results)

All 2007 2006

All Journal Article (5 results) (of which Peer Reviewed: 2 results) Presentation (2 results)

  • [Journal Article] Local Density of States around Impurity in a Strong Magnetic Field: I. Two-Dimensional System with Parabolic Dispersion2007

    • Author(s)
      D. Yoshioka
    • Journal Title

      Journal of the Physical Society of Japan 76

    • NAID

      110006203538

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
    • Peer Reviewed
  • [Journal Article] Local Density of States around Impurity in a Strong Magnetic Field : I. Two-Dimensional System with Parabolic Dispersion2007

    • Author(s)
      D. Yoshioka
    • Journal Title

      Journal of the Physical Society of Japan 76

      Pages: 24718-24718

    • NAID

      110006203538

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Journal Article] Local Density of States around an Impurity in a Strong Magnetic Field.2007

    • Author(s)
      Daijiro Yoshioka
    • Journal Title

      J. Phys. Soc. Jpn. 76・2

      Pages: 24718-24718

    • Related Report
      2006 Annual Research Report
  • [Journal Article] Real-Space Imaging of Alternate Localization and Extension of Quasi-Two-Dimensional Electronic States at Graphite Surface in Magnetic Fields2006

    • Author(s)
      Y. Niimi, H. Kambara, T. Matsui, D. Yoshioka, H. Fukuyama
    • Journal Title

      Physical Review Letters 97

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
    • Peer Reviewed
  • [Journal Article] Real-Space Imaging of Alternate Localization and Extension of Quasi-Two-Dimensional Electronic States at Graphite Surface in M gnetic Fields2006

    • Author(s)
      Y. Niimi, H. Kambara, T. Matsui, D. Yoshioka, H. Fukuyama
    • Journal Title

      Physical Review Letters 97

      Pages: 23804-23804

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Electronic states of two-dimensional systems around an impurity in a strong magnetic field2007

    • Author(s)
      D. Yoshioka
    • Organizer
      Yukawa International seminar 2007
    • Place of Presentation
      京都大学芝蘭会館
    • Year and Date
      2007-11-16
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Annual Research Report 2007 Final Research Report Summary
  • [Presentation] Electronic states of two-dimensional in a strong magnetic field2007

    • Author(s)
      Yoshioka Daijiro
    • Organizer
      systems around an impurity Yukawa international seminar 2007
    • Place of Presentation
      Shiran Kaikan, Kyoto University
    • Year and Date
      2007-11-16
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary

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Published: 2006-04-01   Modified: 2020-05-15  

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