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

量子材料表现出丰富的电子状态现象学，从超导体到相关绝缘体，产生于元素周期表提供给多组分材料的巨大相空间。材料的大相空间也给表征带来了新的挑战，因为许多材料在晶体结构上表现出变化，而成分、缺陷密度和缺陷类型的微小变化会使这些敏感系统进入不同的电子相。这种潜在的不均匀性和对杂质的极端敏感性使得局部探针技术能够提供高分辨率的电子结构光谱表征，成为量子材料研究的重要工具。扫描探针显微镜方法，最著名的是扫描隧道显微镜和光谱（STM， STS），在原子尺度上提供表面的局部结构和电子表征。在过去的15年里，随着仪器仪表的巨大进步，这种光谱测量现在可以在每个像素上进行，而不是在选定的点上进行，这为电子结构的空间非均匀性研究和与“k空间”图像的联系开辟了道路，该图像通过准粒子干涉（QPI）测量驱动了许多凝聚态物质的理解。这些测量为结构、电荷捐赠和缺陷的局部变化的影响提供了前所未有的见解，同时使我们能够测量电子散射的方式，从而深入了解电子状态的对称性和纹理，例如超导间隙和拓扑特征。在这里，我们要求对现有的cfi资助的1K STM/AFM系统进行SPM控制器升级，该系统具有3T磁场耦合到APRES腔室，以允许量子材料领域所需的高质量光谱测量，因为现有控制器不允许获得足够高质量的数据以映射电子结构的局部变化或产生高质量的QPI测量所需的灵活性，以令人信服地回答该领域的关键问题。本文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：稀土方网材料的拓扑特性，极性铁基超导体的超导表面结构，以及薄膜中拓扑超导性的研究。每个都需要高空间和能量分辨率来进行电子结构的真实和/或k空间表征，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制度。

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.