Vibrational spectroscopy with a scanning tunnelling microscope: The role of the tip

使用扫描隧道显微镜进行振动光谱：尖端的作用

• 批准号: 221025572
• 负责人: Professor Dr. Jörg Kröger
• 金额: --
• 依托单位: Fachgebiet Experimentalphysik I
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/221025572?language=en
• 关键词: Vibrational; spectroscopy; scanning; tunnelling; microscope

Inelastic electron tunnelling spectroscopy is an important technique, which enables the investigation of vibrational or magnetic excitations at the atomic scale. Vibrational spectroscopy adds chemical sensitivity to the capabilities of a scanning tunnelling microscope and thus represents an important means in, e.g., surface chemistry. It further enables the analysis of magnetic excitations such as single-atom spin flips. Such investigations are crucial to the development of magnetic data storage devices at the ultimate size. However, very often the excitation cross sections in inelastic electron tunnelling are weak. Further, in vibrational spectroscopy out of the manifold of possible vibration modes only a few modes or even none are usually observed in the spectra. Selection rules have been developed to rationalize these observations in terms of the electronic structure of the adsorbate and substrate and the symmetry of the vibrational modes. The role of the tip, however, has scarcely been discussed – both experimentally and theoretically. The main target of this project is filling this gap by systematically investigating prototypical single-atom and single-molecule vibrational spectra with controllably modified tips.

非弹性电子隧道光谱是在原子尺度上研究振动或磁激发的一种重要技术。振动光谱增加了扫描隧道显微镜的化学灵敏度，因此代表了例如表面化学中的一种重要手段。它还可以分析磁激发，如单原子的自旋翻转。这样的研究对于开发最终尺寸的磁性数据存储设备至关重要。然而，在非弹性电子隧穿中，激发截面往往很弱。此外，在振动光谱学中，在可能的振动模式的流形之外，通常在光谱中只观察到几个模式，甚至没有观察到。根据吸附物和衬底的电子结构和振动模的对称性，制定了选择规则来使这些观察结果合理化。然而，无论是在实验上还是在理论上，针尖的作用都很少被讨论。这个项目的主要目标是通过系统地研究典型的单原子和单分子振动光谱来填补这一空白。