Two-band model for halogen-bridged mixed-valence transition-metal complexes. II. Electron-electron correlations and quantum phonons.
Two-band model for halogen-bridged mixed-valence transition-metal complexes. II. Electron-electron correlations and quantum phonons.
复制标题
卤素桥混合价过渡金属配合物的双能带模型。
DOI：
--
复制
发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Loh
中科院分区：
文献类型：
--
作者：
Weber;Gammel;Bishop;Loh
我们研究了卤素桥接的混合价过渡金属线性链配合物（{ital MX}链）中电子-电子相互作用的影响，应用一个简单的3/4填充的两波段离散紧密结合（扩展）peerls - hubbard模型，该模型具有现场和场间电子-声子耦合。我们采用了多种方法：微扰理论、Hartree-Fock近似和经典绝热声子极限下的精确对角化，以及允许有限声子频率的变分方法，即量子声子和同位素效应。由于该模型结构的丰富性，这种多种方法已被证明是获得完整图像所必需的。我们研究了在基态和激发态的广泛参数范围内电子-电子和电子-声子相互作用之间的竞争。我们将重点放在与{电子MX}链相关的值上，探究{电子X}和{电子M}在{电子X}=Cl、Br和I以及{电子M}=Pt、Pd和Ni（跨越电子-声子相互作用为主到电子-电子相互作用为主的材料）之间的实验变化。
We study the effects of electron-electron interactions in halogen-bridged mixed-valence transition-metal linear-chain complexes ({ital MX} chains) applying a simple 3/4-filled two-band discrete tight-binding (extended) Peierls-Hubbard model with both on-site and intersite electron-phonon couplings. We employ a variety of methods: perturbation theory, Hartree-Fock approximation, and exact diagonalization in the limit of classical adiabatic phonons, and a variational approach allowing for a finite phonon frequency, i.e., quantum phonons and isotope effect. This variety of methods has proved necessary to obtain a complete picture, due to the structural richness of this model. We investigate the competition between the electron-electron and electron-phonon interactions in a wide range of parameter regimes for both ground and excited states. We focus on values relevant to the {ital MX} chains, probing the experimental variation as {ital X} and {ital M} are varied among {ital X}=Cl, Br, and I and {ital M}=Pt, Pd, and Ni (spanning electron-phonon-interaction-dominated to electron-electron-interaction-dominated materials).