Photoinduced Vibronic Soft mode Dynamics in Ferroelectric Quantum Cooperative Phenomena

铁电量子合作现象中的光致电子振动软模动力学

基本信息

批准号：
17340088
负责人：
TAKESADA Masaki
金额：
$ 9.29万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17340088/
关键词：
photo induced phase transition quantum paraelectrics inorganic ferroelectrics vibronic soft mode soft mode dynamics bismuth lavered perovskite photoinduced quantum cooperative phenomenon photoinduced dielectric susceptibility ダイナミクス低振動数

项目摘要

Phase transition and its control by external stimulation have attracted much attention because of not only for basic research but also for wide applications. In particular, sensitive response to external stimulations including light can be extended in the cooperative system close to phase transition point. However, many previous works have focused mainly on organic strongly correlated electron systems. An exploration of new system for a photoinduced phase transition is important subject for further research progress. Recently, in the quantum paraelectric perovskites, SrTiO3 and KTaO3, an anomalous increase of dielectric constant has been observed as a new photoinduced cooperative phenomenon. In the present study we investigate extremely low frequency Raman spectra under UV excitation on perovskites and bismuth-layered perovskites to clarify the dynamical property on photoinduced cooperative phenomena of the quantum paraelectrics and ferroelectrics. In this study we obtained the followi … More ng conclusions.1. A perfect softening of the ferroelectric mode has been observed in the isotope-induced ferroelectric SrTi18O3 by a high-resolution technique using a Sandercock-type tandem Fabry-Perot interferometer. The mechanism of the phase transition is concluded to be an ideal displacive-type with perfect softening. From the difference between the soft mode behavior of quantum paraelectric SrTi16O3 and ferroelectric SrTi18O3, the photoinduced cooperative phenomenon observed in quantum paraelectrics should originate in a vibronic coupling between the ferroelectric soft mode and a photoinduced state.2. An appearance of new central peak related with a photoinduced state and an anomalous instability of the soft mode behavior were observed in layered perovskite oxides by the high-resolution light scattering technique. The obtained results are the first report of the Raman scattering spectra that indicate the existence of photoinduced state. Further systematical investigation using the high resolution light scattering technique will discover a new class of a quantum ferroelectric cooperative phenomenon. Less

相变及其通过外部刺激的控制引起了很多关注，这不仅是基础研究，而且对广泛的应用。特别是，对包括光在内的外部刺激的敏感反应可以在接近相转换点的合作系统中扩展。但是，许多以前的作品主要集中在有机的强度相关的电子系统上。探索用于光诱导的相变的新系统对于进一步的研究进度是重要的主题。最近，在Srtio3和KTAO3的量子副钙钛矿中，饮食常数的异常增加已被视为一种新的光诱导的合作现象。在本研究中，我们研究了极低的频率拉曼光谱在钙钛矿和二叶层的perovskites上的紫外线兴奋下，以阐明量子paraelectrics和铁电的光诱导的合作现象的动态特性。在这项研究中，我们获得了Forowowi…更多结论1。使用SanderCock型串联Fabry-Perot干涉仪，通过高分辨率技术在同位素诱导的铁电SRTI18O3中观察到了铁电模式的完美软化。相变的机理得出结论是理想的位移型，具有完美的软化。从量子副SRTI16O3和铁电SRTI18O3的软模式行为之间的差异中，在量子paraelectrics中观察到的光诱导的合作现象应起源于铁电软模式和光诱导状态之间的振动耦合。2。通过高分辨率的光散射技术，在分层的钙岩氧化物中观察到了与光诱导状态和软模式行为异常不稳定性相关的新中央峰的出现。获得的结果是拉曼散射光谱的第一份报告，表明存在光诱导的状态。使用高分辨率光散射技术进行进一步的系统研究将发现一类新的量子铁电合作现象。较少的

项目成果

期刊论文数量（0）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Ferroelectric Phase Transition in Bi-Layered Perovskite Sr_2Bi_4Ti_5O_<18>

双层钙钛矿Sr_2Bi_4Ti_5O_<18>中的铁电相变

DOI：
发表时间：
2007
期刊：
Ferroelectrics 346
影响因子：
0
作者：
M. Takesada;M. Itoh;A. Onodera;and T. Yagi;Masaki TAKESADA;Tadahiko ISHIKAWA;Seiko MOURI
通讯作者：
Seiko MOURI

High Carrier Mobility Coupled With Quantum Paraelectric Fluctuation

高载流子迁移率与量子顺电涨落相结合