THEORETICAL STUDY IN NANO-PHYSICS OF MAGNETIC ATOM BRIDGES CONTROLLED BY THE STM TIP MANIPULATIONS - NANO-STRUCTURE, NANO-MAGNETISM

STM 尖端操控控制磁原子桥的纳米物理理论研究 - 纳米结构、纳米磁性

基本信息

批准号：
13650026
负责人：
NAKANISHI Hiroshi
金额：
$ 2.24万
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：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

We investigated the nano-physics : nano-lattice-structure, nano-magnetism, and quantum transport, of the magnetic atom bridges constructed between a tip of a scanning tunneling microscope (STM) and a solid surface with the aid of first-principles calculation based on the density functional theory.We show the origin of a change in the magnetic state induced by the STM-tip manipulation and how the change in the magnetic state affects the electron transport phenomena by use of the Fe atom bridge of the simple structure, the linear chain structure. As a result of total energy calculation, the Fe atom bridge of the linear chain structure is unstable and its lattice is too weak to show the change in the magnetic state. The stable atom bridge is of the zigzag chain structure, whose magnetic state is always high-spin ferromagnetic stateWe searched the stable structure of the atom bridge whose lattice structure is enough strong to show a change in the magnetic state. We have found such a stable … More structure. That is the twisted ladder structure. The Fe atom bridge with a twisted ladder structure is stable enough to undergo changes in its magnetic state via compression in length. We showed that it is possible to control the magnetic state by the STM-tip manipulations.We have also investigated the magnetic properties of magnetic alloy atom bridges. In the case of an Fe_<1-x>Ni_x alloy atom bridge, we have found that the atoms maintain a considerably large magnetic moment (about 3μB for an Fe atom and about 0.9μB for a Ni atom), and that the mean magnetic moment per atom in the atom bridge decreases linearly as x increases. In the case of an Fe_xV_<1-x> alloy atom bridges shows a strong contrast with that of the Fe_<1-x>Ni_x alloy atom bridges, and similarities with the bulk of the corresponding alloy, except for the case of x=1.0. In the Fe_<1-x>V_x alloy atom bridge, a V atom has no magnetic moment, and an Fe atom has a smaller magnetic moment than that in the bulk Fe crystal. The magnetic moment of the Fe atom in the Fe-V alloy atom bridge is strongly reduced by the Fe-V atom mixing. These results give us the atom bridge version of the Pauling-Slater curve.Furthermore, we have determined the spin transport phenomena trough these atom bridges. We think that such a systematic investigation gives us the important and useful information in order to establish a basis for the design and fabrication of the atom bridge related nano-spin-electronics devices. Less

我们借助第一性原理计算研究了扫描隧道显微镜 (STM) 尖端和固体表面之间构建的磁性原子桥的纳米物理：纳米晶格结构、纳米磁性和量子输运基于密度泛函理论。我们利用简单结构的铁原子桥展示了STM尖端操纵引起的磁态变化的起源以及磁态变化如何影响电子传输现象，线性的总能量计算结果表明，线性链状结构的Fe原子桥不稳定，其晶格太弱，无法表现出磁性状态的变化，而稳定的原子桥为锯齿状链状结构，其磁性。态始终是高自旋铁磁态我们搜索了原子桥的稳定结构，其晶格结构足以显示磁态的变化，我们发现了这样一个稳定的结构，那就是扭曲的梯子。具有扭曲阶梯结构的铁原子桥足够稳定，可以通过长度压缩来改变其磁性状态。我们表明可以通过 STM 尖端操作来控制磁性状态。我们还研究了磁性。在Fe_<1-x>Ni_x合金原子桥的情况下，我们发现原子保持相当大的磁矩（Fe原子约为3μB，Ni原子约为0.9μB）。原子），并且原子桥中每个原子的平均磁矩随着 x 的增加而线性减小，在 Fe_xV_<1-x> 合金原子桥的情况下，与 Fe_<1-x>Ni_x 的情况形成鲜明对比。合金原子桥，与相应合金的本体相似，除了x=1.0的情况之外，在Fe_<1-x>V_x合金原子桥中，V原子没有磁矩， Fe 原子的磁矩比块状 Fe 晶体中的磁矩小 Fe-V 合金原子桥中 Fe 原子的磁矩因 Fe-V 原子混合而强烈减小。鲍林-斯莱特曲线的版本。此外，我们还确定了通过这些原子桥的自旋输运现象，我们认为这样的系统研究为我们提供了重要且有用的信息，以便为原子的设计和制造奠定基础。桥相关纳米自旋电子器件较少。