Dephasing dynamics of photoexcited state in correlated electron system

相关电子系统中光激发态的相移动力学

• 批准号: 16340085
• 负责人: IWAI Shinichiro
• 金额: $ 10.43万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16340085/
• 关键词: Correlated electron system; Photoinduced phase transition; Polarization dephasing; Mott insulator; Charge order; 超高速分光; 縮退4光波混合

Photo-response of correlated electron (CE) system has attracted much attention because of their ultrafast dynamics aspects. In this research project, I) We have investigated dephasing dynamics of photoexcited state in one-dimesional Mott insulator [Ni(chxn)_2Br]Br_2 by using 2-pulse degenerative four-wave mixing (DFWM), II) ultrafast photoinduced insulator-to metal transition (PIMT) was detected in two-dimensional organic conductor (BEDT-TTF)_2X by mid-IR femtosecond pump-probe spectroscopy for the first time.I)In the DFWM study of [Ni(chxn)_2Br]Br_2, i) for strong excitation condition, the slower decay component (6 ps) of DFWM signal appears, while only sub-ps component is observable for the weak excitation. ii) A temperature dependence of the slow decay for the strong excitation can not be understood in terms of the holon-doublon (h-d) cluster-optical phonon interaction. The temperature dependence of the dynamics can be summarized as follows; a) sub-ps component, which is detected fo … More r T>30 K and becomes shorter for T<100 K, b) several ps component which becomes shorter for T >100 K. The relaxation process of b) can be explained by using the interaction between the carrier and the optical phonon. Nevertheless, the a) is suggested to be related to the magnon excitation since the temperature dependence of the decay constants and their fractions resemble the temperature dependence of the magnetic susceptibility. Moreover, for b), although, the frequency of the interacting optical phonon is evaluated to be same as that of for weak excitation limit, coupling constant is smaller for one order of magnitude. These results indicate that 1) h-d cluster, which is generated by the strong excitation, is scattered by phonon and magnon, 2) the coupling constant between the h-d cluster and optical phonon is markedly suppressed, 3) resultantly, decay reflecting the magnon scattering is considered to appear.II)In the research of the two-dimensional organic conductor (BEDT-TTF)_2X, ultrafast and efficient (>100 molecules /photon) photoinduced insulator-to metal transition was observed. The critical slowing down of the photoinduced metallic state and the coherent phonon reflecting the inhomogeneous structure of the photoinduced domain.Our results will provide the useful information for designing the material for ultarfast CE switching devise whose mechanisms are third order optical nonlinearity or photoinduced phase transition, respectively. Less

相关电子（CE）系统的照片反应由于其超快动态方面引起了很多关注。 In this research project, I) We have investigated dephasing dynamics of photoexcited state in one-dimesional Mott insulator [Ni(chxn)_2Br]Br_2 by using 2-pulse degenerative four-wave mixing (DFWM), II) ultrafast photoinduced insulator-to metal transition (PIMT) was detected in two-dimensional organic conductor (BEDT-TTF)_2X by在[Ni（CHXN）_2Br] BR_2的DFWM研究中，MID-IR飞秒泵探针光谱法。 ii）无法通过holon-doublon（h-d）群集 - 光学声子相互作用来理解慢衰变的温度依赖性。动力学的温度依赖性可以总结如下； a）sub-ps分量，被检测到的fo…更多的r t> 30 k，对于t <100 k，b）几个PS分量变短，几个PS分量对于t> 100 k变短。b）可以通过使用载体和光学声子之间的相互作用来解释b）的放松过程。然而，由于衰减常数及其馏分的温度依赖性类似于磁敏感性的温度依赖性，因此建议A）与磁通兴奋有关。此外，对于b），尽管将相互作用的光音子的频率评估为与弱兴奋极限相同，但对于一个数量级，耦合常数较小。这些结果表明，1）由强烈兴奋产生的h-d簇被声子和大小分散，2）h-d簇和光学声子之间的耦合常数被明显抑制，3）显着，衰减，反映了镁散射的衰减。观察到了分子 /光子）光诱导的绝缘体到金属转变。光诱导的金属状态和反映光诱导域不均匀结构的相干声子的临界减速。您的结果将为设计材料设计用于Ultarfast CE开关设计的材料的有用信息，该材料分别是其机制为三阶光学非线性或光诱导的相变的机制。较少的

项目成果

Photoinduced melting of a stripe-type charge-order and metallic domain formation in a layered BEDT-TTF-based organic salt

• DOI: 10.1103/physrevlett.98.097402
• 发表时间: 2007-03-02
• 期刊: PHYSICAL REVIEW LETTERS
• 影响因子: 8.6
• 作者: Iwai, S.;Yamamoto, K.;Nishio, Y.
• 通讯作者: Nishio, Y.

光媒体および光素子

光学介质和光学元件

• 发表时间: 2005

Coherent control of charge and lattice dynamics in a photoinduced neutral-to-ionic transition of charge-transfer compound

电荷转移化合物光诱导中性到离子转变中电荷和晶格动力学的相干控制

• 发表时间: 2006
• 期刊: Phys. Rev. Lett. 96
• 作者: M.Fujiwara;A.I.Titov;T.Kawabata et al.;M.Uchida et al.;S.Nakayama et al.;S.Iwai;S.Iwai;S.Iwai
• 通讯作者: S.Iwai

Ultrafast Phase Control in One-Dimensional Correlated Electron Systems

一维相关电子系统中的超快相位控制

• 发表时间: 2006
• 期刊: Journal of the Physical Society of Japan 75
• 作者: S.Iwai;H.Okamoto
• 通讯作者: H.Okamoto

Photoinduced phase transtion in tetrathiafulvalene-p-chloranil(TTf-CA) observed in femtosecond reflection spectroscopy

飞秒反射光谱观察到四硫富瓦烯-对四氯苯醌（TTf-CA）的光致相变

• 发表时间: 2004
• 期刊: Phys.Rev.B 70
• 作者: M.Fujiwara;A.I.Titov;T.Kawabata et al.;M.Uchida et al.;S.Nakayama et al.;S.Iwai;S.Iwai;S.Iwai;Shinichiro Iwai;S.Iwai;Shinichiro Iwai;S.Iwai;S.Iwai;H.Okamoto;H.Okamoto;S.Iwai;H.Okamoto;H.Okamoto;H.Okamota
• 通讯作者: H.Okamota