Spin-polarized scanning tunneling microscopy on ultrathin iron films on Be(0001)

Be(0001) 上超薄铁膜的自旋偏振扫描隧道显微镜

• 批准号: 339482673
• 负责人: Dr. Stefan Krause
• 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: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/339482673?language=en
• 关键词: Spin; polarized; scanning; tunneling; microscopy

Within this project ultrathin iron films prepared on a Be(0001) surface under ultrahigh vacuum conditions will be investigated using spin-polarized scanning tunneling microscopy. We expect the iron film to continue the hexagonal close packed atomic lattice of the beryllium substrate, resulting in the Epsilon-phase of the iron structure. The magnetism of Epsilon-iron is not yet unambiguously clear and consequently subject of many ongoing scientific debates. So far, Epsilon-iron has been realized experimentally in bulk samples under extreme high pressure. Our approach allows for the first time the direct investigation of magnetism in ultrathin and extremely pure Epsilon-iron films with atomic precision. The lattice stress induced by the substrate simulates external pressure of up to several 100 GPa, resulting in a considerable compression of the Epsilon-iron film. With increasing film thickness the atomic lattice is expected to relax into the intrinsic Epsilon phase and finally into the conventional body centered cubic phase. At the Fe/Be(0001) interface interesting interactions are expected between the two-dimensional electron gas in beryllium and the local magnetic moments of the iron film, which will be decisive for the magnetic properties of the iron film. Spin-polarized scanning tunneling experiments will allow to access the magnetic state as a function of film thickness and temperature and therefore will shed new light onto the magnetism of Epsilon-iron.

在本计画中，我们将利用自旋极化扫描隧道显微镜来研究在真空条件下在Be（0001）表面上所制备的铍铁薄膜。我们期望铁膜继续铍衬底的六方密排原子晶格，导致铁结构的ε相。ε-铁的磁性还不是很清楚，因此许多正在进行的科学辩论的主题。到目前为止，实验上已经在极高压下的大块样品中实现了ε-铁。我们的方法允许第一次直接调查的磁性在超纯和极纯的ε-铁膜与原子精度。由衬底引起的晶格应力模拟高达几百GPa的外部压力，导致ε-铁膜的相当大的压缩。随着膜厚度的增加，原子晶格预计将松弛成本征Epoxy相，并最终进入常规的体心立方相。在Fe/Be（0001）界面处，铍中的二维电子气与铁膜的局部磁矩之间存在着有趣的相互作用，这将决定铁膜的磁性。自旋极化扫描隧道实验将允许访问作为膜厚度和温度的函数的磁状态，因此将揭示新的光到磁性的ε-铁。