Theoretical study in nano-structure-physics of magnetic atom bridges and molecular bridges

磁性原子桥和分子桥纳米结构物理理论研究

基本信息

批准号：
16510075
负责人：
NAKANISHI Hiroshi
金额：
$ 1.92万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16510075/
关键词：
Atom bridge Molecular bridge nanostructure STM Magnetism First principles calculations Quantized conductance gas adsorption STM

项目摘要

We investigated the nano-physics of the magnetic atom bridges and molecular bridges with the aid of the first-principles calculations based on the density functional theory. After we researched the stability and magnetic properties of the magnetic atom bridge constructed between metal surface and STM-tip, we started researching the magnetic molecular bridges, which have their highly-reproducible structures supporting the magnetic atoms. We treated the tape-porphyrin with the transition metal atom, M, as a centre metal atom, in which M=Sc, Ti, V, Cr, Mn, Fe, Co, Ni and Cu. We found that in the case of M= Sc, Ti, V, Cr, Mn and Fe, the systems are the ferromagnetic metals. In the case of M=Co, Ni and Cu, the systems are insulators. In order to investigate the origin of the electronic property of these tapes, we also calculated the corresponding isolated unit of M porphyrin molecule, whose meso-and β-carbons are terminated by hydrogen atoms. As the results, The molecular orbital, which has the charge distribution on the meso-and β-carbons, becomes the wide energy bands when the molecules connect each other and construct the tape. So in the case where their Eigen energies lie near the Fermi energy, the corresponding tape-porphyrin is conductor.In addition, we found that the metal-insulator transition occurs when a CO molecule adsorbed on the Fe tape-porphyrin. We clarified that such a metal-insulator transition is caused by the hybridization of the dxz and dyz orbitals of Fe with the II^* g orbitals of CO molecule.

我们根据密度功能理论的第一原理计算，研究了磁原子桥和分子桥的纳米物理。在研究金属表面和STM-TIP之间构建的磁原子桥的稳定性和磁性之后，我们开始研究磁分子桥，它们具有支持磁原子的高度可复制的结构。我们用过渡金属原子M将胶带处理为中心金属原子，其中m = SC，Ti，ti，v，cr，mn，mn，fe，co，co，ni和cu。我们发现，在M = SC，Ti，V，Cr，Mn和Fe的情况下，系统是铁磁金属。对于M = CO，Ni和Cu，系统是绝缘子。为了研究这些磁带的电子特性的起源，我们还计算了M卟啉分子的相应孤立单位，其中氧和β-碳纤维被氢原子终止。结果，当分子相互连接并构造胶带时，在中索和β碳中具有电荷分布的分子轨道变成了宽的能带。因此，在其本征能位于费米能量附近的情况下，相应的胶带 - 孢子蛋白是导体。此外，我们发现，当co分子吸附在fe胶带孢子林上时，金属 - 绝缘体过渡会发生。我们澄清说，这种金属 - 绝缘体的转变是由Fe的DXZ和Dyz轨道与CO分子的II^* G轨道的杂交引起的。