Que Yande, Kumar Amit, Lodge Michael S, Tong Zhengjue, Lai Marcus Kar Fai, Tao Wei, Cui Zhenhao, Shivajirao Ranjith, Jia Junxiang, Lee Siew Eang, Weber Bent
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore.
Department of the Built Environment, College of Design and Environment, National University of Singapore, 4 Architecture Drive, 117566, Singapore.
Nanotechnology. 2023 Aug 22;34(45). doi: 10.1088/1361-6528/acebf7.
Ultra-low temperature scanning tunnelling microscopy and spectroscopy (STM/STS) achieved by dilution refrigeration can provide unrivalled insight into the local electronic structure of quantum materials and atomic-scale quantum systems. Effective isolation from mechanical vibration and acoustic noise is critical in order to achieve ultimate spatial and energy resolution. Here, we report on the design and performance of an ultra-low vibration (ULV) laboratory hosting a customized but otherwise commercially available 40 mK STM. The design of the vibration isolation consists of a T-shaped concrete mass block (∼55t), suspended by actively controlled pneumatic springs, and placed on a foundation separated from the surrounding building in a 'room-within-a-room' design. Vibration levels achieved are meeting the VC-M vibration standard at >3 Hz, reached only in a limited number of laboratories worldwide. Measurement of the STM's junction noise confirms effective vibration isolation on par with custom built STMs in ULV laboratories. In this tailored low-vibration environment, the STM achieves an energy resolution of 43eV (144 mK), promising for the investigation and control of quantum matter at atomic length scales.
通过稀释制冷实现的超低温扫描隧道显微镜和能谱（STM/STS）能够深入洞察量子材料和原子尺度量子系统的局部电子结构，这是其他方法无法比拟的。为了实现极致的空间和能量分辨率，有效隔绝机械振动和声学噪声至关重要。在此，我们报告了一个超低温振动（ULV）实验室的设计与性能，该实验室配备了一台定制但其他部分为市售的40 mK STM。隔振设计包括一个T形混凝土质量块（约55吨），由主动控制的气动弹簧悬吊，并采用“房中房”设计放置在与周围建筑隔开的地基上。所达到的振动水平在>3 Hz时符合VC-M振动标准，全球仅有少数实验室能达到这一标准。对STM结噪声的测量证实了其隔振效果与ULV实验室中定制的STM相当。在这种经过特殊设计的低振动环境中，STM实现了43 μeV（144 mK）的能量分辨率，有望用于在原子长度尺度上对量子物质进行研究和控制。
