Welcome to a fascinating journey into the realm of ultra-low temperature scanning tunneling microscopy and spectroscopy (STM/STS). In a groundbreaking case study conducted by Yande Que, Amit Kumar, Michael S. Lodge, and their esteemed colleagues from the Division of Physics and Applied Physics at Nanyang Technological University, Singapore, delve into the design and performance of an ultra-low vibration (ULV) laboratory hosting a customized, commercially available 40-mK scanning tunneling microscope.
The Quest for Unrivaled Insight
Ultra-low temperature scanning tunneling microscopy and spectroscopy hold the key to unrivaled insights into the local electronic structure of quantum materials and atomic-scale quantum systems. To achieve this, effective isolation from mechanical vibration and acoustic noise is crucial for ultimate spatial and energy resolution.
In this case study, the researchers present a tailored low-vibration environment featuring a T-shaped concrete mass block suspended by actively controlled pneumatic springs. This innovative design, implemented in a “room-within-a-room” structure, aims to achieve vibration levels meeting the VC-M vibration standard at >3 Hz – a feat accomplished in only a limited number of laboratories worldwide.
Benchmarking Commercially Available Technology
The focal point of this study is the performance benchmarking of a UNISOKU USM1600 mK-STM – a commercially available ultra-low temperature scanning tunneling microscope. Customized with a two-axis vectorized superconducting magnet, this system provides cooling to a base temperature of 40 mK at the STM head. The integration of RF coaxial cables allows signal transmission up to 10 GHz frequencies, opening avenues for advanced nanoelectronic device measurements.
Laboratory Design for Precision
The laboratory design is a critical aspect of achieving ultimate performance in ultra-low vibration environments. The researchers detail their approach, incorporating a “room-within-a-room” solution that is structurally decoupled from the surrounding building. This involves a meticulous excavation process and the adoption of passive and active isolation techniques, including a massive inertia block supported by pneumatic isolators and/or active dampers.
Unveiling the Achievements
In this meticulously crafted ultra-low vibration laboratory, the UNISOKU USM1600 mK-STM achieves remarkable results. With an energy resolution of 43 μeV (144 mK), the STM promises groundbreaking investigations and control of quantum matter at atomic length scales.
Dive Deeper
For a comprehensive understanding of the design, challenges, and achievements of this ultra-low vibration laboratory, we invite you to download the full case study below. Embark on a journey through the intricacies of precision instrumentation, vibration isolation, and the pursuit of unlocking the secrets of quantum matter.
