Optical control of magnetic/dielectric properties by a phase contoled sub-cycle near infrared pulse in strongly correlated materials

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K14317
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics I
• Research Institution: Tohoku University
• Principal Investigator: Kawakami Yohei 東北大学, 理学研究科, 助教 (60731172)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 超高速ダイナミクス / 光誘起相転移 / 光強電場効果 / 光磁気効果 / 第二高調波発生 / 強相関電子系 / 有機超伝導体 / 量子スピン液体

Outline of Final Research Achievements

Optical controls of magnetic and dielectric properties in strongly correlated materials have been investigated using ultrashort near infrared (NIR) pulses. We have performed time-resolved experiments using the extremely short pulse (instantaneous field intensity >100 MV/cm, pulse width <6 fs). As a result, we have observed an ultrafast disappearance of ferroelectricity (complete photoinduced insulator to metal transition) in charge ordered organic crystal a-(BEDT-TTF)2I3 and novel optical functions (stimulated emission and second harmonic generation) sensitive to a superconducting transition in an organic superconductor k-(BEDT-TTF)2Cu[N(CN)2]Br. Furthermore, ultrafast polarization rotation induced by an extremely short circularly polarized pulse has been detected in a quantum spin liquid material a-RuCl3. This result indicates a possibility of femto-second control of the magnetic property.

Free Research Field

光物性

Academic Significance and Societal Importance of the Research Achievements

超伝導や強磁性、強誘電性、マルチフェロイクスといった特徴的な電気・磁気的性質を示す強相関電子系は次世代超高速エレクトロニクスを支える候補材料のひとつである。本研究では、その電子物性の超高速光制御を検証した。極限的な単一サイクル～サブサイクル光を用いた実験から、電荷秩序型有機物質における強誘電性の光消失、非BCS型有機超伝導体における非摂動論的な電荷駆動や新奇な光機能性を観測し、さらに、量子スピン液体におけるフェムト秒磁気操作の可能性も示された。これらの結果は、強相関電子系物質と高強度極短パルス光を組み合わせた次世代超高速エレクトロニクスの基幹技術の創生につながる。