| Project/Area Number |
18K03481
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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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| Review Section |
Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
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| Research Institution | Chiba University |
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Principal Investigator |
Oto Kenichi 千葉大学, 大学院理学研究院, 教授 (30263198)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2018: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
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| Keywords | 量子ホール効果 / 光渦 / エッジ状態 / 2次元電子系 / 強磁場 / 光起電力 / キラリティ / スピン |
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| Outline of Final Research Achievements |
The optical vortex (OV) which has a spiral wave front with the axial and radial components of electric fields carries an optical orbital angular momentum with a chirality. We studied the electron transport in a two-dimensional electron system made of GaAs/AlGaAs single-heterostructure under the OV irradiation to investigate the interaction between the OV and quantum Hall electron system which has chiral edge states along the sample boundary. To avoid the influence of the simple photoconductive effect, we measured the resistance deviation (dR) due to the OV irradiation by using lock-in technique. The dR peaks or dips can be observed in the QH regime, where the chiral edge states act as electron transport channels along the sample boundary. The origin of the observed dR may be attributed by the change of the scattering rate and/or by the modification of the number of excited electrons due to the sign of the topological number m of irradiated OV.
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| Academic Significance and Societal Importance of the Research Achievements |
光渦は、らせん状の等位相面を持ち、放射状の電場や中心軸を周回する方向の回転電場が発生するキラリティを持った光であり、いわゆる光の軌道角運動量を有した電磁波である。光渦が半導体に吸収されたときに生じる励起電子の状態は、通常の光励起によるものとは異なる可能性があり、新しい性質を与える可能性がある。量子ホール電子系は強い磁場により、電子のエネルギーはもちろん、その軌道角運動量やスピン角運動量が明確に定まっており、光励起によって生じた電子による電流やそのスピン状態を計測することで、未解明である光渦と電子系との相互作用を詳しく調べることができ、本研究では、その一端を捉えることができた。
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