Theoretical Study of Quantum Transport Phenomena through an Atom Sized Contact.

通过原子大小接触的量子输运现象的理论研究。

• 批准号: 08650032
• 负责人: KASAI Hideaki
• 金额: $ 1.34万
• 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: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650032/
• 关键词: quantized conductance; STM; atom bridge; electron correlation; Hubbard model; metal surface; ハバ-ド・モデル; ハバ-ドモデル

When the tip of a scanning tunneling microscope is brought into contact with a metal surface and then lifted up slowly, an atom-sized contact is formed between the tip and the surface. An atom-sized bridge is thus formed and its cross section consists of a few atoms to a few tens of atoms. Conductance of the bridge is measured as a function of the stretching length of the bridge, while the tip is lifted up. A stepwise variation of the conductance is experimentally observed roughly in units of 2e^<>h. In order to satisfy requirements for downsizing from mesoscopic scale to atomic scale in electronics, it is necessary to examine various phenomena occurring in such atom-sized systems. With this in mind, we examine the effects of the constricted structure of the atom-sized bridge and the effects of the Coulomb interaction between electrons on the quantized conductance through an atom-sized bridge. The obtained results are summarized as follows.1. The effects of the constricted structure of … More the atom-sized bridge :Stepwise variation of the conductance is disturbed by the broken symmetry of the shape of the atom-sized bridge.2. The effects of the intra-site Coulomb interaction between electrons :At finite temperatures, the Coulomb interaction causes various types of electron-electron scattering processes, inter-subband as well as intra-subband scattering processes and Umklapp as well as normal scattering processes, and strongly affects the quantum transport property of an atom-sized bridge. As a result, the following are derived.(1) At the conductance plateau, the deviation of the conductance value from multiples of the universal value of 2e2/h grows as the temperature is decreased. This temperature dependence is stronger for stronger Coulomb interactions.(2) Near the step, a valley structure appears as a function of the stretching length of the bridge. As the temperature is decreased, the valley gets narrower. The depth of the valley grows significantly, as the Coulomb interaction becomes stronger. Less

当将扫描隧道显微镜的尖端与金属表面接触，然后缓慢抬起时，将在尖端和表面之间形成原子大小的接触。因此形成了原子大小的桥，其横截面由几个原子组成至几十原子。桥的电导是根据桥的拉伸长度的函数测量的，而尖端则抬起。在2e^<> h的单位中大致观察到电导的逐步变化。为了满足从介质量表到电子量表的缩小尺寸的要求，有必要检查在这种原子尺寸系统中发生的各种现象。考虑到这一点，我们检查了原子尺寸桥的狭窄结构的影响，以及电子之间通过原子尺寸桥的库仑相互作用对量化电导的影响。所获得的结果总结如下1。 ……更多原子尺寸桥的狭窄结构的影响：电导的逐步变化被原子尺寸桥的形状的破碎对称性扭曲。2。电子之间库仑相互作用的影响：在有限的温度下，库仑相互作用会导致各种类型的电子电子散射过程，间隔间以及子带内散射过程和UMKLAPP以及正常的散射过程，并强烈影响ATOMSIPSIPANSIPANSIPANSIPSIPANS的量子运输特性。结果，得出以下内容。（1）在电导平台上，电导值从2e2/h的通用值的倍数中偏离，随着温度的提高。这种温度依赖性对于更强的库仑相互作用更强。（2）在步骤附近，山谷结构是桥梁的拉伸长度的函数。随着温度的降低，山谷变窄。随着库仑相互作用变得更强，山谷的深度显着增长。较少的

项目成果

H.Kasai: "On the Molecular Orientation Dependence of Dynamical Processes on Solid Surfaces : Dissociative Adsorption and Scattering" Springer Series in Solid-State Sciences(Springer,Berlin). 121. 99-111 (1996)

H.Kasai：“论固体表面动态过程的分子取向依赖性：解离吸附和散射”固体科学中的施普林格系列（施普林格，柏林）。

W.A.Dino: "Role of the Rotational Motion in the Dissociative Adsorption and Associative Desorption Dynamics of D_2/Cu(111)" Physical Review Letters. 78. 286-289 (1997)

W.A.Dino：“旋转运动在 D_2/Cu(111) 解离吸附和缔合解吸动力学中的作用”物理评论快报。

Y.Kawahito, H.Kasai, H.Nakanishi, and A.Okiji: "Effects of intra-site Coulomb interaction on quantized conductance in a quantum wire between an STM-tip and a metal surface" Suface Science. 409. L709-L714 (1998)

Y.Kawahito、H.Kasai、H.Nakanishi 和 A.Okiji：“位内库仑相互作用对 STM 尖端和金属表面之间量子线中量子电导的影响”Suface Science。

K.Hasegawa, H.Kasai, W.A,Din^^〜o, and A.Okiji: "Dynamics of STM-Induced CO Desorption from Cu(111)" Journal of the Physical Society of Japan. 67. 4018-4021 (1998)

K.Hasekawa、H.Kasai、W.A、Din^〜o 和 A.Okiji：“STM 诱导的 Cu(111) CO 解吸动力学”日本物理学会杂志 67. 4018-4021 (1998)。 ）

H.Nakanishi: "Inelastic Scattering from the Translational Vibration Mode on Molecules Adsorbed on Solid Surfaces" Surface Science. 363. 391-396 (1996)

H.Nakanishi：“固体表面吸附分子平移振动模式的非弹性散射”表面科学。