Research on the ground state of non-quantized quantum Hall systems
| Project/Area Number |
12640308
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | The University of Tokyo |
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Principal Investigator |
YOSHIOKA Daijiro The University of Tokyo, Graduate School of Arts and Sciences Professor, 大学院・総合文化研究科, 教授 (30114713)
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| Co-Investigator(Kenkyū-buntansha) |
SHIABATA Naokazu The University of Tokyo, Graduate School of Arts and Sciences Research Associate, 大学院・総合文化研究科, 助手 (40302385)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2001: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | two-dimensional electrons / strong magnetic field / quantum Hall effect / stripe states / density matrix renormalization method / pairing state / by-layer quantum Hall system / 半導体 / 電荷密度波状態 / ウィグナー結晶 / 密度行列繰り込み群法 |
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| Research Abstract |
The first aim of the research was to obtain an comprehensive understanding as to why states at the same even-denominator filling factor have different ground states at various Landau levels. For this aim we performed investigations using the Hartree-Fock meanfield theory and the density matrix renormalization group (DMRG) study, which gives the most include Fermi liquid state, pairing state, and stripe state. Furthermore we clarified how the ground state evolves as we change the filling factor in the third and fourth lowest Landau levels.
The second aim of the research was to obtain an understanding of the orientation of the stripe phase. For this aim we performed Hartree-Fock calculation in the presence of an external periodic potential. We clarified that when the external periodic potential that is originated from the surface morphology has period that is longer than that of the stripe state, the stripes orient themselves perpendicular to the external potential. As the cause of the orientation we identified the tendency towards the Wigner crystallization as the origin. Namely, it causes modulation of the stripe, and forms an energy gap at the Fermi level. Then compressibility acquires anisotropy that causes the orientation of the stripe.
Furthermore, we investigated how the pairing state in the second lowest Landau level evolves when the layer separation is increased in a bi-layer systems. Thus we obtained an phase diagram on the layer-separation and the inter-layer tunneling strength.
Apart from these investigations, we investigated the ground state at total filling one. For these investigations we obtained various new findings. We are planning to publish these results in the near future.
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Report
(3 results)
Research Products
(21 results)
