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.

在该项目中，将使用自旋偏振扫描隧道显微镜研究超高真空条件下在 Be(0001) 表面上制备的超薄铁膜。我们预计铁膜将延续铍基底的六方密堆积原子晶格，从而产生铁结构的 Epsilon 相。厄普西隆铁的磁性尚未明确，因此成为许多正在进行的科学争论的主题。到目前为止，Epsilon-铁已经在极高压力下在大块样品中通过实验实现。我们的方法首次允许以原子精度直接研究超薄且极纯的厄普西隆铁薄膜中的磁性。基底引起的晶格应力模拟高达数百 GPa 的外部压力，导致 Epsilon 铁薄膜产生相当大的压缩。随着薄膜厚度的增加，原子晶格预计会松弛到本征 Epsilon 相，并最终松弛到传统的体心立方相。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预计会发生有趣的相互作用，这对于铁膜的磁性能至关重要。自旋极化扫描隧道实验将允许获得作为薄膜厚度和温度函数的磁性状态，因此将为研究厄普西隆铁的磁性提供新的线索。