Femtosecond Dynamics of Photoinduced Phase Transitions

光致相变的飞秒动力学

基本信息

批准号：
13304024
负责人：
SUEMOTO Tohru
金额：
$ 30.12万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2004
项目状态：
已结题

项目摘要

The ultrafast dynamics of the photoinduce phase transitions has not been well understood before starting this project. We studied the dynamic behavior of these phenomena in pico-and femto-second regions, by using time-resolved luminescence, reflectance and Raman spectroscopy. The materials studied are (1)quasi-one-dimensional platinum complexes, (2)nickel complexes, (3)vanadium bronze, (4)divalent ion spin-cross-over complexes, and (5)quantum paraelectrics.Followings are the main achievements.1.In quasi-one-dimensional halogen-bridged platinum complexes, we investigated the self-trapped excitons, which are important as the intermediate states of photoinduced lattice rearrangements, by using femtosecond luminescence spectroscopy. The motion of the wave-packets is captured as a movie for the first time. Importance of the non-radiative transitions has been revealed, based on the halogen-ion dependence of the decay dynamics.2.In Ni-Br complexes, we found a luminescence with a large Stokes … More shift, which shows the importance of electron-lattice interactions in the excited state, although it has been believed that the electron correlation is more important than the electron-phonon interaction in the ground state.3.We applied femtosecond spectroscopy to the spin ladder system, α'-NaV_2O_5 for the first time. Elementary excitations were coherently generated and a new mode was found near the twice of the spin gap energy. The charge disordering process induced by photo-excitation has been observed as a reflectance change and a response faster than thermal effect was found. Photo-induced phase transition or charge disordering is suggested to be responsible for this phenomenon. These investigations opened the doorway to dynamical studies in this material.4.In spin crossover complexes containing divalent Fe ions, we found a new phase that cannot be produced through thermal process. By tuning the excitation photon energy, specific spin states are generated selectively.5.A giant dielectric response was found in SrTiO_3 and KTaO_3, by irradiating with ultraviolet photons. Less

在开始该项目之前，尚未对光诱导的相变的超快动力学进行充分的理解。我们通过使用时间分辨的发光，反射率和拉曼光谱法研究了这些现象在PICO和FEMTO秒区域中的动态行为。 The materials studiod are (1)quasi-one-dimensional platinum complexes, (2)nickel complexes, (3)vanadium bronze, (4)divalent ion spin-cross-over complexes, and (5)quantum paraelectrics.Followings are the main achievements.1.In quasi-one-dimensional halogen-bridged platinum complexes, we investigated the self-trapped excitons, which are important as通过使用飞秒发光光谱法，光诱导的晶格重排的中间状态。首次将波包的动作作为电影捕获。基于衰减动力学的卤素离子依赖性，已经揭示了非辐射过渡的重要性。2.在Ni-Br络合物中，我们发现了具有较大stokes的发光……更多的转变……更多的变化，这表明了令人兴奋的状态中电子宽松互动的重要性，尽管已经相信，电子相关性比phlonon相互作用更重要。首次α'-nav_2o_5的旋转梯子系统的光谱。基本的兴奋是相干产生的，并在自旋差距能量的两次附近发现了一种新模式。发现由光启示引起的电荷无序过程被认为是反射率的变化，并且比热效应更快。照片诱导的相变或电荷无序被认为是该现象的原因。这些研究为该材料中的动态研究打开了门口。4。在包含二价Fe离子的自旋跨界复合物中，我们发现了一个无法通过热过程产生的新阶段。通过调整兴奋光子能量，选择性生成特定的自旋态。5。在SRTIO_3和KTAO_3中发现了巨型二世响应，通过使用紫外照片照射。较少的

项目成果

期刊论文数量（78）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

時間分解発光分光法による超高速格子緩和の研究

使用时间分辨发射光谱研究超快晶格弛豫

DOI：
发表时间：
2004
期刊：
レーザー研究 32
影响因子：
0
作者：
末元徹
通讯作者：
末元徹

Photoindueced phase transition of a spin-crossover complex studied with the combination of SR and laser

SR 和激光相结合研究自旋交叉配合物的光致相变

DOI：
发表时间：
2002
期刊：
Surface Review and Letters 9
影响因子：
0
作者：
K.Takahashi;M.Kamada;Y.Fukui;K.Fukui;T.Tayagaki;K.Tanaka
通讯作者：
K.Tanaka

L.H.Machtoub, G.El Machtoub, J.Shimoyama, T.Suemoto: "Elementary excitations investigated by femtosecond Raman spectroscopy in underdoped cuprates"Physica C. 392-396. 291-294 (2003)

L.H.Machtoub、G.El Machtoub、J.Shimoyama、T.Suemoto：“通过飞秒拉曼光谱研究欠掺杂铜酸盐的基本激发”Physica C. 392-396。

DOI：
发表时间：
期刊：
影响因子：
0
作者：
通讯作者：

H.Kamioka, S.Saito, M.Isobe, Y.Ueda, T.Suemoto: "Coherent magnetic oscillation in the spin ladder system α'-NaV_2O_5"Physical Review Letter. 88. 127201-1 (2002)

H.Kamioka、S.Saito、M.Isobe、Y.Ueda、T.Suemoto：“自旋系统阶梯 α-NaV_2O_5 中的相干磁振荡”物理评论信 88. 127201-1 (2002)。

DOI：
发表时间：
期刊：
影响因子：
0
作者：
通讯作者：

Photoinduced spin transition probed by x-ray diffraction

DOI：
10.1103/physrevb.69.020101
发表时间：
2004-01
期刊：
Physical Review B
影响因子：
3.7
作者：
N. Huby;L. Guérin;E. Collet;L. Toupet;J. Ameline;H. Cailleau;T. Roisnel;T. Tayagaki;Koichiro Tanaka
通讯作者：
N. Huby;L. Guérin;E. Collet;L. Toupet;J. Ameline;H. Cailleau;T. Roisnel;T. Tayagaki;Koichiro Tanaka