MRI: Development of an Ultralow-Temperature Scanning Tunneling Microscope for Investigation of Quantum Phenomena in Complex Materials and Nanostructures

本项目将开发一种独特的扫描隧道显微镜（STM）系统，该系统可在超低温（50 mK）、高磁场（高达11 T）和超高真空（10-10 torr）下工作。该仪器结合了一个强大的定制稀释冰箱/磁铁系统，两个用于样品转移和制备的特高压室，以及一个自制的高分辨率STM。超低温STM （ULTSTM）仪器将被安置在一个最先进的设施内，在一个巨大的浮动地板上建造的双层隔音和射频屏蔽外壳内。在这个先进的设施中，声学、射频和隔振相结合的降噪效果将保证ULTSTM系统具有前所未有的性能。利用这种独特的仪器，飞米计尖端稳定性和微伏能量分辨率光谱将成为可能，这种组合为在各种纳米级系统和复杂材料中获取重要的量子现象提供了可能性。该仪器将有助于研究材料中的量子现象的各种研究活动，从非常规超导体和量子相变的研究到自旋组件中的量子纠缠的研究。参与该研究项目的研究生和本科生将学习最先进的扫描探针显微镜技术和纳米制造方法，这是工业界和学术界都非常感兴趣的。显微镜在开辟科学新领域方面起着关键作用。扫描探针显微镜（SPMs）是新一代功能强大的显微镜，其工作原理是在微观尺度上映射探针与样品之间的局部相互作用。这些新型仪器将物质成像的能力提升到了原子尺度，并为从半导体到生物分子的一切事物开辟了新的视角。拟议的项目将开发一种独特的扫描隧道显微镜（STM），将测量的前沿推进到超低温，那里发生重要的电子现象。物质的异常状态或量子相干过程对热搅拌极为敏感；因此，它们只能在接近绝对零度的温度下观察到。这台新仪器将以亚埃分辨率绘制材料中的电子波，从而获得前所未有的量子行为细节。研究人员将不仅仅是被动的观察者，因为拟议的仪器允许他们通过一次操纵一个原子来调整原子景观。这种对物质的精细控制将用于进行前所未有的实验，以仔细检查我们目前对物质中电子现象的理论理解。参与该项目的学生将学习设计复杂的科学仪器，并使用它们来解决材料物理中一些最具挑战性的问题。

Technical AbstractA unique scanning tunneling microscope (STM) system that operates at ultra-low temperatures (50 mK), at high magnetic fields (up to 11 T) and in ultra-high vacuum (10-10 torr) will be developed in this project. An instrument that combines a powerful custom-built dilution refrigerator/magnet system, two UHV chambers for sample transfer and preparation, and a home-built high-resolution STM will be constructed. The ultra-low temperature STM (ULTSTM) instrument will be housed in a state-of-the-art facility inside double-walled acoustic and rf-shielded enclosures, which are constructed on a massive floating floor. The noise reduction resulting from the combination of acoustic, rf, and vibration isolation in this advanced facility will guarantee an unprecedented performance for the ULTSTM system. Femtometer tip stability and microvolt-energy-resolution spectroscopy will be possible with this unique instrument" a combination that opens up the possibility to access important quantum phenomena in a variety of nanoscale systems and complex materials. This instrument will contribute to diverse research activities in the study of quantum phenomena in materials, from the study of unconventional superconductors and quantum phase transitions to the study of quantum entanglement in spin assemblies. The graduate students and undergraduate students involved in this research project will learn state-of-the-art scanning probe microscopy techniques and nanofabrication methods that are of strong interest to both industry and academia.Non-technical AbstractMicroscopes have been pivotal in opening new frontiers in science. Scanning probe microscopes (SPMs) are a new generation of powerful microscopes that operate by mapping on the microscopic scale the local interaction between a pointed probe and the sample. These novel instruments have taken the ability to image matter to the atomic scale and have opened fresh perspectives on everything from semiconductors to biomolecules. The proposed project will develop a unique scanning tunneling microscope (STM) that advances the frontiers of measurement to ultra-low temperatures where important electronic phenomena occur. Unusual states of matter or quantum coherent processes are extremely sensitive to thermal agitation; hence, they are only observable at temperatures close to absolute zero. The new instrument will make it possible to obtain unprecedented details of quantum behavior by mapping electronic waves in materials with sub-Angstrom resolution. The researchers will be more than just passive observers, as the proposed instrument allows them to tailor the atomic landscape by manipulating matter one atom a time. This fine control over matter will be used to perform unprecedented experiments that scrutinize our current theoretical understanding of electronic phenomena in matter. The students participating in this project will learn to design sophisticated scientific instrumentation and use them to attack some of the most challenging problems in physics of materials.