1995 Fiscal Year Final Research Report Summary
Strongly correlated phases arising from spin and layr degrees of freedom in the fractional quantum Hall system
| Project/Area Number |
06640500
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
物性一般(含基礎論)
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| Research Institution | The University of Tokyo |
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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)
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| Project Period (FY) |
1994 – 1995
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| Keywords | fractional quantum Hall effect / composite particle picture / strong correlation / spin degrees of freedom / double quantum well / quantum dot |
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| 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.
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