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

在开始使用时间分辨率的材料的材料是（1）准二维的材料，在启动这些现象之前，在pico and and femto-second区域的这些现象之前，没有很好地理解光引诱相变的超快动力学铂络合物，（2）钒青铜，（4）Antum Paraelectrics.froplowings是主要成就。1。在准二维卤素桥的铂金配合物中，我们研究了使用光诱导的Latty重排的自我捕获的激子，并利用使用Faptysecond的latty重排光谱。激发的肉质中的晶格相互作用比基态的电子电话相互作用。3。我们对自旋梯子系统进行了飞秒的光谱，这是第一次被视为由照片引起的。与热效应的响应更快兴奋的光子能量是选择的。5在SRTIO_3和KTAO_3中发现

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）

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

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