Rapid and efficient control of physical properties by terahertz pulses in electronic-type ferroelectrics

2015 Fiscal Year Final Research Report

• Project/Area Number: 25247049
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Condensed matter physics I
• Research Institution: The University of Tokyo
• Principal Investigator: OKAMOTO Hiroshi 東京大学, 新領域創成科学研究科, 教授 (40201991)
• Co-Investigator(Kenkyū-buntansha): YADA Hiroyuki 東京大学, 大学院新領域創成科学研究科, 助教 (60573144)
• Co-Investigator(Renkei-kenkyūsha): HORIUCHI Sachio 産業技術総合研究所, フレキシブルエレクトロニクス研究センター, チーム長 (30371074) ; KANODA Kazushi 東京大学, 大学院工学系研究科, 教授 (20194946)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 光物性 / フェムト秒レーザー / 誘電体物性 / テラヘルツ分光 / 分子性固体

Outline of Final Research Achievements

In this study, by using a terahertz electric-field pulse, we succeeded in controlling ferroelectric polarizations in the sub-picosecond time scale in electronic-type organic ferroelectrics (TTF-CA, α-(ET)2I3, and croconic acid), in which their polarizations originate from intra- or inter-molecular π-electrons transfers. Moreover, in the paraelectric phase of TTF-CA, we showed that a terahertz electric field gives rise to a large polarization, which reaches about 20 % of the polarization in its ferroelectric phase. We also demonstrated that these rapid and large responses of the polarizations are characteristic of electronic-type dielectrics. Our method of polarization controls using terahertz pulses presented in this study can be utilized for rapid optical modulation and optical switching, so that related studies will be extensively performed.

Free Research Field

光物性