1998 Fiscal Year Final Research Report Summary
QUANTUM TRANSPORT OF TWO-DIMENSIONAL ELECTRON SYSTEMS IN STRONG MAGNETIC FIELDS AT LOW TEMPERATURES : QUANTUM HALL EFFECT AND LOCALIZATION
| Project/Area Number |
07404015
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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 | GAKUSHUIN UNIVERSITY |
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Principal Investigator |
KAWAJI Shinji GAKUSHUlN UNIVERSITY,DEPARTMENT OF PHYSICS,PROFESSOR, 理学部, 教授 (00080440)
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| Co-Investigator(Kenkyū-buntansha) |
OKAMOTO Tohru GAKUSHUIN UNIVERSITY,DEPARTMENT OF PHYSICS,RESEARCH ASSOCIATE, 理学部, 助手 (60245371)
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| Project Period (FY) |
1995 – 1998
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| Keywords | strong magnetic field / two-dimensional electron system / quantum transport / quantum Hall effect / quantized Hall resistance / electron localization / fractional quantum Hall effect / composite fermion |
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| Research Abstract |
Results obtained on quantum Hall effect and localization in two-dimensional electron systems are followings :
1.Integer quantum Hall effect. Butterfly-type Hall bars with different width between 10 and 200 mum were made from GaAs/AIGaAs heterostructure wafers to investigate current dependences of quantized Hall resistance and dissipation at temperatures below 1 K.Collapse of the quantized Hall resistance was observed at lower current than the critical current for breakdown of dissipatioless current flow. A phenomenological model for the electronic states in a Hall bar was proposed to explain the relation between the collapse of the quantized Hall resistance and the breakdown of the quantum Hall effect.
2.Fractional quantum Hall effect. Electrical conductivity of composite fermions at the half-filled Landau level of GaAs/A1GaAs heterostructures was measured at temperatures below 1.5 K.The temperature dependence was investigated based on a recent theory of quantum correction to Drude conductivity due to mutual interaction of composite fermions
3.Localization. Temperature dependence and magnetic field dependence of diagonal resistivity of Si-MOS inversion layers in insulating phase were studied and results were explained by a model based on Aharonov-Bohm effect in exchange interaction between electrons in a Wigner solid.
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