Performance benchmarking of an ultra-low vibration laboratory to host a commercial millikelvin scanning tunnelling microscope

TL;DR

This paper details the design and performance of an ultra-low vibration laboratory that enables a 40mK scanning tunnelling microscope to achieve high energy resolution, facilitating advanced quantum material studies.

Contribution

It introduces a novel vibration isolation setup for ultra-low temperature STM, achieving vibration levels comparable to specialized labs and enabling high-resolution quantum measurements.

Findings

Vibration levels meet VC-M standards at >3 Hz

STM achieves an energy resolution of 43 μeV (144 mK)

Vibration isolation performance is comparable to custom ULV laboratories

Abstract

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 40mK 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 43ueV (144 mK), promising for the investigation and control of quantum matter at atomic length scales.