Ultrafast spectral dynamics of shift current
| Project/Area Number |
17H02914
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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 | Institute of Physical and Chemical Research |
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Principal Investigator |
Ogawa Naoki 国立研究開発法人理化学研究所, 創発物性科学研究センター, チームリーダー (30436539)
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| Co-Investigator(Kenkyū-buntansha) |
五月女 真人 国立研究開発法人理化学研究所, 創発物性科学研究センター, 特別研究員 (40783999)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥18,460,000 (Direct Cost: ¥14,200,000、Indirect Cost: ¥4,260,000)
Fiscal Year 2019: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
Fiscal Year 2018: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2017: ¥11,440,000 (Direct Cost: ¥8,800,000、Indirect Cost: ¥2,640,000)
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| Keywords | シフト電流 / シフト光電流 / 光物性 |
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| Outline of Final Research Achievements |
Shift current refers to the photocurrent in materials with broken inversion symmetry, originating from the spontaneous shift of electron clouds upon photoexcitation in real-space via the topological nature of the electronic bands. To unveil the ultrafast and less-dissipative natures of the shift current, we study the spectral dynamics by analyzing the THz electromagnetic waves generated from photoexcited carriers. The shift current is found to appear faster than the experimental time-resolution (~100 fs) with a tensor response to the incoming photon polarization, and shows a distinct time profile from that of the conventional optical rectification. Importantly, the experimental shift current spectra in several ferroelectric semiconductors nicely compare with those deduced by the first-principles calculations based only on the crystal structures.
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| Academic Significance and Societal Importance of the Research Achievements |
近年, 古典的な電子分極から, 異常ホール効果, 磁気スキルミオン, トポロジカル絶縁体, ワイル半金属等の量子物質まで, 様々な物質系/物理現象においてベリー位相が表舞台に出てきている. 「シフト電流」は電子バンド間のベリー接続の差が直接観測にかかる興味深い物理現象であるとともに, 新規太陽電池や高速の赤外光センサーへの応用も期待されている. 本研究によって, 新たな非接触/高速の光電流分光法の有効性とともに, シフト電流の応答が結晶構造のみからの第一原理計算によって予測できることが示された. またフォノン等による散逸や, 有限のコヒーレンスなどの存在も明らかとなった.
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Report
(4 results)
Research Products
(25 results)
