Investigations of local excitation of two-dimensional electron systems by helical THz waves
| Project/Area Number |
15H03673
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | University of Tsukuba |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
三沢 和彦 東京農工大学, 工学(系)研究科(研究院), 教授 (80251396)
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| Project Period (FY) |
2015-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥17,160,000 (Direct Cost: ¥13,200,000、Indirect Cost: ¥3,960,000)
Fiscal Year 2018: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2017: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2016: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2015: ¥8,190,000 (Direct Cost: ¥6,300,000、Indirect Cost: ¥1,890,000)
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| Keywords | 半導体 / 二次元電子系 / 偏光状態任意操作 / THz / 局所励起 / フェムト秒 / 量子状態 / 光照射効果 |
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| Outline of Final Research Achievements |
In this research project, we have generated polarization-twisting pulses with the polarization rotation frequency in the THz regime, and investigated a local excitation effect of two-dimensional electron gas samples by illuminating the polarization shaped pulses. For this purpose, we have fabricated and characterized GaAs/AlGaAs modulation-doped quantum well Hall-bar samples and encapsulated h-BN/MoS2/h-BN heterostructure field-effect transistors. We have, for the first time, successfully observed the switching of the direction of the photovolatge depends on the envelope helicity of the polarization-twisting pulses. These observations are explained by the circular photogalvanic effect and the classical edge photocurrent generated by acceleration of free carriers in the vicinity of the sample edge by the optical electric field of the polarization-twisting pulses.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では無磁場下非磁性体において時間反転対称性の破れた状態の実現・観測に成功した。これは無磁場下での量子ホール状態の観測、光照射による物質の量子相状態の動的制御のための重要なステップと位置付けられる。ベクトル整形ねじれ偏光パルスの回転振動数を広い範囲で調整可能であり、高い自由度で偏向状態を設定可能であることが、THz領域における物質と偏向光の関わる現象の研究にとても強力な手段であることが示された。今後、さまざまな物質系にこの手法が適用されると考えられる。本研究の成果は無もしくは低磁場下において動作するスピントロニクスデバイス、円偏光を検出するTHz帯光センサの開発に寄与すると期待される。
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Report
(5 results)
Research Products
(34 results)
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[Journal Article] Circularly polarized near-field scanning optical microscope for investigations of edge states of a two-dimensional electron system2015
Author(s)
Shintaro Nomura, Syuhei Mamyouda, Hironori Ito, Yusuke Shibata, Tomoya Ohira, Luno Yoshikawa, Youiti Ootuka, Satoshi Kashiwaya, Masumi Yamaguchi, Hiroyuki Tamura, Tatsushi Akazaki
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Journal Title
Appl. Phys. A
Volume: 121
Issue: 4
Pages: 1341-1345
DOI
NAID
Related Report
Peer Reviewed / Open Access
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[Presentation] 光誘起端状態の検出に向けて2015
Author(s)
野村晋太郎
Organizer
東北大学電気通信研究所共同プロジェクト研究会
Place of Presentation
ベルサンピアみやぎ泉（宮城県黒川郡大和町）
Year and Date
2015-10-08
Related Report
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[Presentation] Circularly Polarized Near-field Scanning Optical Microscope for Investigations of Edge States of a Two-dimensional Electron Gas2015
Author(s)
S. Nomura, S. Mamyouda, H. Ito, Y. Shibata, T. Ohira, L. Yoshikawa, Y. Ootuka, S. Kashiwaya, M. Yamaguchi, H. Tamura and T. Akazaki,
Organizer
APNFO-10
Place of Presentation
Hakodate Research Center for Fisheries and Oceans （北海道函館市）
Year and Date
2015-07-08
Related Report
Int'l Joint Research
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