【作者】 李爱玉；

【导师】 朱梓忠；

【作者基本信息】 厦门大学 ， 理论物理， 2006， 博士

【摘要】 近年来,准一维纳米材料的研究引起了凝聚态物理、化学及材料科学家们的广泛关注,成为纳米材料研究的热点。准一维纳米材料包括纳米丝,纳米线(棒)、纳米管、纳米带、纳米同轴电缆、异质结与超晶格纳米线等。金属原子链和金属纳米线是一维纳米材料中在纳米尺度上比较特殊、在应用上比较有前景的两种结构,不仅是研究电子输运和力学参数尺寸与维度依赖的理想研究体系,同时也可作为纳米连接以及功能组元在纳米电子、光电器件中发挥不可替代的作用。目前有关准一维金属原子链和金属纳米线的研究已经成为纳米材料科学领域的中心课题之一。材料的物理性质是材料应用的基础。对准一维纳米材料的结构稳定性及电子性质的理论研究能够为准一维纳米材料的制备、结构的人工控制提供有意义的理论指导,是准一维纳米材料应用的前提和基础。近年来,实验上成功制得了悬挂于两个金电极之间的稳定的金单原子链,这一成果被认为是低维物理以及纳米科技发展的一个里程碑,此后人们遍把视线移到各种不同金属形成的原子链上。Ti和Ni分别属于前后过渡金属元素。Ti原子的电子组态是3d~24s~2和Ni原子的电子组态3d~24s~2有强烈的互补关系。为此,本论文采用第一性原理方法,系统地对Ti、Ni、TiNi合金原子链的结构稳定性和电子性质(包括磁性质)进行了系列性的研究,并过渡到具有一定截面半径和不同截面形状的金属纳米线,考察金属纳米线电子性质的尺寸演化和结构关联。期望本论文的研究和结论能为金属纳米线的开发和应用提供有意义的理论指导。本论文可分为两部分。第一部分介绍了研究工作所涉及的基本理论和第一原理方法。首先介绍了密度泛函理论,包括密度泛函理论的基本思想、Hobenberg- Kohn定理、Kohn-Sham方程和交换关联近似(局域密度近似和广泛梯度近似)等。接着介绍了本研究工作中所采用的具体的电子结构计算方法,即平面波展开的第一性原理赝势法。并对基于平面波赝势法的VASP程序包的特点作了介绍。第二部分共有五章,分别介绍我们的研究工作和结果:更多还原

【Abstract】 In resent years, quasi one-dimensional (1-D) materials, including nanowires (nanorods), nanotubes, nanobelts, heterojunction and superlattice nanowires, have attracted great attentions in the scientists of condense matter physics and chemistry, and become an important research subject in the nanomaterial science. Especially, metallic atomic chains and metallic nanowires with special nano-scales are ideal systems for investigating the dependence of electronic, transport, optical, magnetic and mechanical properties on size and dimensionality. In addition, they are expected to play an important role as interconnects and functional components of new electronic and optoelectronic devices. Now the research of the metallic nanowires has already become one of the central subjects in the nanomaterial science.The physical properties of the nanomaterials are the foundation for their applications. So the study on the structure stability and electronic properties of the nanowires will provide valuable theoretical guidance for the preparing and controlled synthesis of 1-D nanomaterials. Recently, the stable gold atomic chains suspended between two gold electrodes were realized in laboratories by two research groups. These experiments have been considered as one of the milestones in the low dimensional physics and nanoscience. Subsequently, atomic chains formed by various metals have been intensively studied both in theory and experiment. Ti and Ni are the pre-transition and latter-transition metals. The electron configurations of Ti and Ni are and , respectively. They are complements of each other. In this dissertation, by using the first-principles calculations based on the density functional theory, we have systematically studied the structural stability, electronic and magnetic properties of Ti, Ni and alloy TiNi chains. We also studied some typical structures of titanium nanowires whose cross sections are planar polygons, and 3d 2 4s23 d8 4s2更多还原