2014 Fiscal Year Final Research Report
Quantum characteristics of graphene reflecting interplay among spin, layer and orbital degrees of freedom and their relations to particle physics
| Project/Area Number |
24540270
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2012-04-01 – 2015-03-31
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| Keywords | グラフェン / ラムシフト / 低次元電子系 / ゲージ理論 / 物性理論 / 素粒子論 |
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| Outline of Final Research Achievements |
Graphene is an eminent system of Dirac electrons and, when stacked to form a few layers, reveals even richer electronic characteristics. We explored a new many-body quantum effect in few-layer graphene and its consequences. In a magnetic field bilayer graphene supports eight zero-energy Landau levels with twofold orbital degeneracy. We pointed out that this orbital degeneracy is lifted by quantum fluctuations of the valence band (Dirac sea), leading to the "Lamb shift" as in the hydrogen atom. This "orbital" Lamb shift governs the structure of the lowest Landau level and is observable via the quantum Hall effect. For trilayers the presence of this effect makes them, depending on their stacking pattern, still richer in variety and in function.
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| Free Research Field |
数物系科学
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