Charge Order and Photoinduced Nonlinear Dynamics in Low-Dimensional Molecular Conductors

低维分子导体中的电荷有序和光致非线性动力学

基本信息

批准号：
12640361
负责人：
YONEMITSU Kenji
金额：
$ 2.37万
依托单位：
Okazaki National Research Institutes
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

In (DCNQI)_2Cu, conductivity and magnetism are correlated through hybridization of π and d orbitals. In the insulator phase under high pressure, three-fold lattice distortion and paramagnetism coexist. Peierls and Mott mechanisms work cooperatively. Even the level difference between these orbitals is not optimal, self-doping takes place to stabilize this lattice-distorted phase. This fact is demonstrated by the exact diagonalization studies for a two-band Peierls-Hubbard model.In organic charge-transfer complex, TTF-CA, a transition takes place from the paraelectric neutral phase to the ferroelectric ionic phase at a low temperature or under high pressure. Photoexcitation also triggers the transition. The time-dependent Schrodinger equation is solved for an extended Peierls-Hubbard model with alternating potentials. Dynamics of charge density and lattice displacements from the ionic phase is studied to reproduce a threshold in phtoexcitation intensity. The Fourier analysis of the time- … More dependent ionicity clarifies the fast excitonic motion, the slow lattice vibration, and the even slower collective motion of neutral-ionic domain boundaries. Photoexcitation produces ionic domains with the opposite polarization to the initial one, by which the lattice order quickly decays. This is consistent with the faster evolution of the second harmonic generation than the photoreflectivity.In halogen-bridged binuclear metal complexes, various charge- and lattice-ordered phases appear depending on the ligand, halogen ion, and counter ion. The mechanisms of the respective electronic phases are investigated in Peierls-Hubbard models. Especially with iodine, platinum, and ligand pop, halogen ion, and counter ion. The mechanisms of the iodine, platinum, and ligand pop, there appear charge-density-wave (CDW) and chargepolarization (CP) phases. Photoexcitation within the hysteresis loop triggers a transition phase does not transfer charge among binuclear units at low energies, and does not grow CDW nuclei even at high energies. Less

在（DCNQI）_2CU中，电导率和磁性通过π和D轨道的杂交相关。在高压下的绝缘体阶段中，三重晶格失真和顺磁性共存。 Peierls和Mott机制合作起作用。即使这些轨道之间的水平差异也不是最佳的，也可以进行自兴奋剂，以稳定这个晶格延伸的相位。在有机电荷转移复合物TTF-CA中，通过精确的对角线研究的精确对角线研究证明了这一事实，这是从降压离子相位到低温或高压下的铁电离子相的过渡。光激发还触发过渡。对于具有替代势的扩展PEIERLS-HUBBARD模型，可以解决时间依赖性的Schrodinger方程。研究了来自离子相的电荷密度和格子位移的动力学，以重现pHToExitation强度的阈值。时间的傅立叶分析 - 更依赖的离子性阐明了快速的令人兴奋的运动，慢速晶格振动以及中立离子域边界的较慢的集体运动。光激发产生与初始层相反极化的离子域，晶格顺序很快就会衰减。这与第二次谐波生成的更快演变一致。在卤素桥的二元金属络合物中，各种电荷和晶格有序的相位都取决于配体，卤素离子和反离子。在PEIERLS-HUBBARD模型中研究了各个电子相的机制。尤其是碘，铂和配体流行，卤素离子和反离子。碘，铂和配体POP的机制，出现电荷密度波（CDW）和电荷偏振（CP）阶段。磁滞回路内的光激发触发过渡阶段不会在低能量下的纤维单位之间转移电荷，即使在高能量下也不会生长CDW核。较少的