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New Method for Quantitative Electronic Structure Calculation

定量电子结构计算新方法

基本信息

批准号：
08640478
负责人：
SAITO Susumu
金额：
$ 0.9万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08640478/
关键词：
Tight-Binding Method Fullerene C_<60>密度汎関数法

项目摘要

New carbon-based materials such as fullerenes and nanotubes can take a variety of topological structures and consequently, have a variety of physical properties. Hence, they are now of high interest not only in scientific fields but also in technological fields as new functional materials and device materials. On the other hand, due to their complicated network structure as well as their large unit-cell size, the first-principles electronic structure study of these interesting materials are often very expensive. Therefore, more simplified quantum mechanical approach, tight-binding method, is now attracting a renewed interest. A quantitatively reliable tight-binding model for carbon has been already constructed. However, in the fullerene-based ionic compounds, the long-range Coulomb interaction (Madelung energy) as well as the Coulomb repulsion between excess electron on each fullerene should be very important but is not included in a usual tight-binding model. We have formulated the tight-binding model in which the above two important terms are properly incorported. The new tight-binding model has been applied to the polymerized K_1Cthe moderate-amplitude charge-density wave state is found to be a possible stable state. The present improvement of the tight-binding method has been proven to be effective. A promising future direction of the tight-binding model, the inclusion of the spin polarization, is also pointed out.

新的碳基材料，如富勒烯和纳米管，可以采取各种拓扑结构，因此，具有各种物理性能。因此，它们现在不仅在科学领域而且在技术领域作为新的功能材料和器件材料受到高度关注。另一方面，由于它们复杂的网络结构以及它们的大的晶胞尺寸，这些感兴趣的材料的第一性原理电子结构研究往往是非常昂贵的。因此，更简单的量子力学方法，紧束缚方法，现在吸引了新的兴趣。一个定量可靠的紧束缚模型的碳已经建成。然而，在基于富勒烯的离子化合物中，长程库仑相互作用（Madelung能量）以及每个富勒烯上的过量电子之间的库仑排斥应该是非常重要的，但通常的紧束缚模型中没有包括。我们建立了紧约束模型，在这个模型中，上述两个重要的术语都得到了适当的解释。将新的紧束缚模型应用于聚合K_1C，发现中等振幅的电荷密度波态是一种可能的稳定态。本文对紧捆法的改进已被证明是有效的。紧束缚模型的一个有前途的未来方向，包括自旋极化，也指出。