Spin friction of single atoms investigated by scanning tunneling microscopy

通过扫描隧道显微镜研究单原子的自旋摩擦

• 批准号: 408119516
• 负责人: Dr. André Kubetzka
• 金额: --
• 依托单位: Institut für Nanostruktur- und Festkörperphysik (INF)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/408119516?language=en
• 关键词: Spin; friction; single; atoms; investigated

Atom manipulation with the tip of a scanning tunneling microscope (STM) is a widespread and straightforward technique to build complex nanostructures in an atom-by-atom fashion. In this project I want to use atom manipulation as an imaging tool to investigate the static and dynamic properties of adatoms on magnetic surfaces. Instead of measuring (spin-dependent) density of states a few atomic distances above the surface, as in standard (spin-polarized) STM, the manipulated adatom can be seen as an extension of the tip probing (spin-dependent) forces right at the surface. The central question of this project is the following: Which interactions influence an adatom's path when it is moved across a magnetic surface? Here, I am especially interested in magnetic interactions beyond the nearest neighbor Heisenberg exchange. Closely related to this question are the aspects of energy dissipation and friction, and to what extend the spin degree of freedom plays a role in these processes. To disentangle different contributions, especially the magnetic from the electronic ones, I will use magnetic as well as non-magnetic tips and adatoms on a variety of surface spin textures such as antiferromagnets, spin spirals, skyrmion lattices and domain walls. Since the manipulation experiments can reveal site-dependent binding strengths of adatoms, it should be possible to estimate to what extent magnetism can influence adatom diffusion and thus growth processes in general. Additional atom diffusion experiments are planned to verify this idea. Furthermore, in cases where the resting or moving adatom acts back onto the local surface spin texture, I will try and exploit this effect to control magnetic states with manipulated ensembles of adatoms.

用扫描隧道显微镜(STM)的尖端操纵原子是一种广泛而直接的技术，可以逐个原子的方式构建复杂的纳米结构。在这个项目中，我想使用原子操纵作为一种成像工具来研究磁性表面上吸附原子的静态和动态性质。与在标准的(自旋极化的)STM中测量表面上方几个原子距离的(自旋相关的)态密度不同，操纵的吸附原子可以被视为尖端探测(自旋相关的)力在表面的延伸。这个项目的中心问题是：当吸附原子在磁性表面上移动时，哪些相互作用会影响它的路径？在这里，我特别感兴趣的是最近的邻居海森堡交换以外的磁相互作用。与这个问题密切相关的是能量耗散和摩擦方面，以及自旋自由度在这些过程中起多大作用。为了区分不同的贡献，特别是磁性和电子的贡献，我将使用磁性和非磁性的尖端和吸附原子在各种表面自旋织构上，如反铁磁体、自旋螺旋、Skyrmion晶格和磁畴壁。由于操纵实验可以揭示吸附原子与位置相关的结合强度，因此应该可以估计磁性在多大程度上可以影响吸附原子的扩散，从而总体上影响生长过程。为了验证这一想法，还计划进行更多的原子扩散实验。此外，在静止或移动的吸附原子作用于局部表面自旋织构的情况下，我将尝试利用这种效应来控制受操纵的吸附原子系综的磁态。