| Project/Area Number |
18540308
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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 |
Condensed matter physics I
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| Research Institution | Yamagata University |
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Principal Investigator |
NONOYAMA Shinji Yamagata University, Faculty of Education, Art, and Science, Professor (50221487)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Atsunobu Yamagata University, Anan National College of Technology, Professor (00217829)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥1,910,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥210,000)
Fiscal Year 2007: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Tunneling Phenomena / Semiconductor / Very Small Region / Electron Correlation / 量子ホール効果 / トンネル電流 / 理論 |
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| Research Abstract |
The integer quantum Hall effect (QHE) and one-dimensional Anderson localization (AL) are limiting special cases of a more general phenomenon, directed localization (DL), predicted to occur in disordered one-dimensional wave guides called "quantum railroads" (QRR). We have investigated the results of recent measurements by Kang et al. of electron transfer between edges of two-dimensional electron systems and identify the first experimental evidence of QRR's in the general, but until now entirely theoretical, DL regime that unifies the QHE and AL.
We have begun by clarifying how disorder affects electron transfer through the barrier. We have done our computer simulations using a recursive Green's function technique. We consider the system with an additional smooth random potential that models the electron Coulomb interaction with donor ions in the doped layer adjacent to the 2DEG's. The transmission peak is found to be sufficiently broad to explain the observed persistence of the conductance peaks. This results are consistent with the absence of features of spin in the data. Temperature dependence of the peak structure is also explained.
To explore this further we performed self-consistent Hartree calculations of the edge channel energies, treating the effects of disorder in a mean-field approximation. The locations of the tunneling maxima predicted by our calculations of the edge channel crossings are in quantitative agreement with the observed positions of the differential conductance peaks.
We have also proposed a simple measurement that should be able to settle unambiguously important issue of the role that spin plays in this system.
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