1988 Fiscal Year Final Research Report Summary
Quantum Hall Effect and Localization: Quantum Effects in Electron Transport
| Project/Area Number |
60060003
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| Research Category |
Grant-in-Aid for Specially Promoted Research
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| Allocation Type | Single-year Grants |
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| Research Institution | Gakushuin University |
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Principal Investigator |
KAWAJI Shinji Gakushuin University, Dept. of Physics, Professor, 理学部, 教授 (00080440)
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| Co-Investigator(Kenkyū-buntansha) |
OKADA Mitsuo University of Tokyo, IIS, Assistant, 生産技術研究所, 助手 (60013158)
ANDO Tsuneya University of Tokyo, ISSP, Associate Professor, 物性研究所, 助教授 (90011725)
KAWABATA Arisato Gakushuin University, Dept. of Physics, Professor, 理学部, 教授 (80013514)
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| Project Period (FY) |
1985 – 1988
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| Keywords | quantum Hall effect / localization / two-dimensional syatems / semiconductor inversion layer / semiconductor heterostructure / 微細構造定数 |
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| Research Abstract |
1. Fractional quantum Hall effect(FQHE): (1) Measurements of energy gaps of 1/3 and 2/3 states showed that there is no electon-hole symmetry. (2)It was found that the 1/7 state is the quantum liquid state.
2. Integral quantum Hall effect(IQHE) and localization: Experiments on Si-MOSFETs showed that the localization depends on the Landau quantum unmber.
3. Magnetoresistance in weak magnatic fields: Anomalous magnetoresistances were observed in heterostructures, Si-MOS and InAs inversion layers.
4. High precision measurements of quantized Hall resistance(QHR): the QHR of Si-MOSFETs was about 0.3 ppm larger than that derived from the electron'anomalous moment and about 0.1 ppm larger than that of GaAs/AlGaAs. These results show that the QHR has a problem in determination of the fine structure constant.
5. Theory of quantized conductance in ballistic transport: Experimental finding of quantized conductance in narrow channels was quantitatively explained.
6. Theory of the IQHE:(1) Rigolous explanation of the IQHE was given based on the topological invariance. (2) Numerical studies were performed on correlation between diagonal and Hall condutivities and effects of symmetries on localization. (4) Hall effect in quantum wires was studied.
7. Formation of 2D systems by high purity heterostructures: Samples used in experiments of this project were fabricated by molecular beam epitaxy.
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