Theoretical study on optical responses of excitons in monolayer transition-metal dichalcogenides
Project/Area Number |
16K05391
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Research Field |
Condensed matter physics I
|
Research Institution | Hokkaido University |
Principal Investigator |
|
Project Period (FY) |
2016-04-01 – 2020-03-31
|
Project Status |
Completed (Fiscal Year 2019)
|
Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2017: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2016: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
|
Keywords | 励起子 / 遮蔽効果 / 光学応答 / 層状物質 / 遷移金属ダイカルコゲナイド / 吸収スペクトル / 誘電関数 / ディラック電子系 / 光吸収 / 動的遮蔽 / 遷移金属カルコゲナイド |
Outline of Final Research Achievements |
Optical excitation in semiconductors generates electrons and holes and the Coulomb attraction causes formation of the electron-hole bound state what we call exciton. In a monolayer transition-metal dichalcogenide, the exciton plays a dominant role in its optical response because there is no dielectric environment giving rise to screening outside the two-dimensional electronic system. In this study, we have developed a theoretical method to evaluate the dynamical screening effect for excitons. We calculated exciton absorption spectra under several types of dielectric material such as organic solvents and compound semiconductor substrates and discussed the control of optical responses.
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Academic Significance and Societal Importance of the Research Achievements |
半導体中の励起子形成に対する動的遮蔽効果は光学応答に影響を及ぼす重要な問題と古くから認識されていたが,非線形固有値問題に帰着され十分な解析がなされていなかった.本研究では,励起子の固有状態を求めることなく,応答関数を直接計算することにより動的遮蔽を考慮した束縛エネルギーを評価する手法を開発し,層状物質の外部環境を制御することで光学応答の変調が可能であることを示した.動作波長の可変性を実現することで光学デバイスへの応用が広がると期待される.
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Report
(5 results)
Research Products
(12 results)