Spatially resolved spectroscopy of Quantum Materials: Scanning probe Microscopy control system for high-resolution tunnelling spectroscopy

量子材料的空间分辨光谱：用于高分辨率隧道光谱的扫描探针显微镜控制系统

• 批准号: RTI-2022-00171
• 负责人: Burke, Sarah
• 金额: $ 10.93万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=743037
• 关键词: Spatially; resolved; spectroscopy; Quantum; Materials

Quantum materials exhibit a rich phenomenology of electronic states ranging from superconductors to correlated insulators, arising from the enormous phase space that the periodic table provides to multicomponent materials. This large phase space of materials also presents new challenges for characterization as many materials exhibit variations in crystal structure, and small changes in composition, defect density and type of defect can tip these sensitive systems into different electronic phases. This potential for inhomogeneity and extreme sensitivity to impurities makes local probe techniques that can provide high resolution spectroscopic characterization of the electronic structure an essential tool for quantum materials research. Scanning probe microscopy methods, most notably Scanning Tunnelling Microscopy and Spectroscopy (STM, STS), provide local structural and electronic characterization of surfaces on the atomic scale. With dramatic advances in instrumentation in the past 15 years, such spectroscopy measurements can now be taken at each pixel, rather than selected points, opening up access to both studies of spatial inhomogeneity of the electronic structure and a connection to the "k-space" picture that drives much of condensed matter understanding through quasiparticle interference (QPI) measurements. These measurements provide unprecedented insight into the influence of local variations in structure, charge donation, and defects, while simultaneously allowing us to measure how electrons scatter providing insight into symmetries and textures of the electronic states, such as the superconducting gap and topological features. Here, we request an SPM controller upgrade for an existing CFI-funded 1K STM/AFM system with 3T magnetic field coupled to an APRES chamber to allow for the high-quality spectroscopic measurements demanded by the Quantum Materials field, as the existing controller does not allow for the flexibility required to obtain sufficiently high-quality data to map local variations in electronic structure or produce high-quality QPI measurements needed to convincingly answer key questions in this area. Three lines of research are described, providing examples of the types of studies possible and their demands on instrumentation: Topological properties of rare-earth square net materials, Surface texture of superconductivity in a polar Fe-based superconductor, and the Search for topological superconductivity in thin films. Each requires high-spatial and energy resolution for real and/or k-space characterization of the electronic structure, and requires access to <4K temperatures and magnetic fields to explore the most exciting regimes of the electronic structures of these materials.

量子材料表现出从超导体到相关绝缘体的丰富电子态现象学，这些电子态现象源于元素周期表为多组分材料提供的巨大相空间。这种材料的大相空间也给表征带来了新的挑战，因为许多材料表现出晶体结构的变化，并且成分、缺陷密度和缺陷类型的微小变化可以使这些敏感系统进入不同的电子相。这种不均匀性和对杂质极度敏感的潜力使得能够提供电子结构高分辨率光谱表征的局部探针技术成为量子材料研究的重要工具。扫描探针显微镜方法，尤其是扫描隧道显微镜和光谱学（STM、STS），可以在原子尺度上提供表面的局部结构和电子表征。随着过去 15 年仪器技术的巨大进步，现在可以在每个像素而不是选定的点进行此类光谱测量，从而为电子结构的空间不均匀性研究以及与“k 空间”图像的联系提供了机会，“k 空间”图像通过准粒子干涉 (QPI) 测量推动了凝聚态物质的理解。这些测量为结构、电荷供给和缺陷的局部变化的影响提供了前所未有的洞察力，同时使我们能够测量电子的散射方式，从而深入了解电子态的对称性和纹理，例如超导能隙和拓扑特征。在这里，我们请求对现有 CFI 资助的 1K STM/AFM 系统进行 SPM 控制器升级，该系统具有与 APRES 室耦合的 3T 磁场，以实现量子材料领域所需的高质量光谱测量，因为现有控制器无法获得足够高质量的数据来映射电子结构的局部变化或产生令人信服的高质量 QPI 测量所需的灵活性。 回答该领域的关键问题。描述了三个研究方向，提供了可能的研究类型及其对仪器的要求的示例：稀土方网材料的拓扑特性、极性铁基超​​导体中超导性的表面织构以及薄膜中拓扑超导性的搜索。每个都需要高空间和能量分辨率来表征电子结构的真实和/或 k 空间特征，并且需要访问 <4K 的温度和磁场来探索这些材料的电子结构的最令人兴奋的状态。