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1995 Fiscal Year Final Research Report Summary

Strongly correlated phases arising from spin and layr degrees of freedom in the fractional quantum Hall system

Research Project

Project/Area Number 06640500
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field 物性一般(含基礎論)
Research InstitutionThe University of Tokyo

Principal Investigator

AOKI Hideo  The University of Tokyo, Graduate School of Science, Associate Professor, 大学院・理学系研究科, 助教授 (50114351)

Project Period (FY) 1994 – 1995
Keywordsfractional quantum Hall effect / composite particle picture / strong correlation / spin degrees of freedom / double quantum well / quantum dot
Research Abstract

The purpose of the present project is to investigate versatile phases arising from spin and/or layr degrees of freedom in the fractional quantum Hall (FQH) system. In the 1995 fiscal year, we have focussed on the composite fermion picture for the double-layr FQH system. In a double system the strength of inter-layr tunnelling enters as a new energy scale.
We have found the following :
・ The composite fermion picture is a good approximation even for the excited states (pseudo-spin wave) in double-layr systems.
・ We can describe the double-layr FQH system with the phase diagram on the tunneling strength and the layr separation. The quantum Hall region is identified from a finite gap in the low-lying excitation (which is exactly the pseudo-spin wave). The composite picture has enabled us to obtaine for the first time the phase diagram for the fractional double-layr system. The quantum Hall region widens dramatically as the Landau-level filling degreases to 1/3,1/5, ..., which is due to the fact that the composite-particle transformation diminishes the interaction while keeping the tunnelling unchanged.
・ We have a vertically coupled double dot if we confine the electrons in a double-layr into quantum dots. We have proposed this system, and have shown that (i) there is a series of new magic numbers in the total angular momentum specific to double dots, and (ii) these magic numbers may be observed with the optical absorption.

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] 中島龍也,青木秀夫: "Composite-fermion analysis of the double-layer fractional quantum Hall system" Physical Review B. 52. 13780-13783 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 今村裕志,P. A. Maksym, 青木秀夫: "Magic numbers and the FIR absorbtion spectrum of vertically coupled quautum dots" Physical Review B, in press.

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 中島龍也,青木秀夫: "分数量子ホール効果と複合フェルミオン描像" 日本物理学会誌. 50. 725-729 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 中島龍也,青木秀夫: "Manifestation of spin degress of freedom in the double fractional quantum Hall system" Physical Review B. 51. 7874-7877 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 青木秀夫: "量子ホール効果の理論(安藤恒也:編)" 丸善, 291 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 青木秀夫,中島龍也: "Composite-fermion analysis of the ferromagnetic spin wave in the fractional quantum Hall system, in 'High Magnetic Field in the Physics of Semiconductors'ed by D. Heiman" World Scientific, 765 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Nakajima and H.Aoki: "Composite-fermion analysis of the double-layr fractional quantum Hall system" Physical Review B. vol.52. 13780-13783 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Imamura, P.A.Maksym, and H.Aoki: "Magic numbers and the FIR absorbtion spectrum of vertically coupled quantum dots" Physical Review B. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Nakajima and H.Aoki: "Fractional quantum Hall effect and composite-fermion picture" Butsuri. vol.50. 725-729 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Nakajima and H.Aoki: "Manifestation of spin degrees of freedom in the double fractional quantum Hall system" Physical Revies B. vol.51. 7874-7877 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Aoki: "Theory of quantum Hall effect, edited by T.Ando" Maruzen. 291 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Aoki and T.Nakajima: "Composite-fermion analysis of the ferromagnetic spin wave in the fractional quantum Hall system in 'High Magnetic Fields in the Physics of Semiconductors' ed.by D.Heiman" World Scientific. 765 (1995)

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

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Published: 1997-03-04  

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