Cryogen-free Ultra-High Vacuum Low Temperature High Field Proximal Probe System for the Exploration of Low Dimensional Materials*

Our versatile cryogen-free low temperature scanning probe microscope (SPM) expands SPM capabilities to ultra-high vacuum (UHV), operating at temperatures down to 4K, and magnetic fields up to 9T. We have created an internal vibration isolation unit that connects to cryogen-free cryostats reducing the noise level sufficiently to operate SPMs. Typical cryogen-free systems are too noisy to operate SPMs. The modular design of this SPM accommodates interchangeable probes, including STM, AFM, and MFM. One of the probes is a novel vertical STM design, enabling scanning tunneling topography and spectroscopy in the presence of in-plane magnetic fields up to 9T. This UHV instrument is equipped with stages for sputtering, e-beam film deposition, and exfoliation for in-situ sample preparation and tip conditioning. The SPM is assembled at room temperature in UHV and a novel low-profile vertical transfer mechanism permits transferring the SPM, without breaking vacuum, to a variable temperature, cryogen-free cryostat and magnet. The integration of all these capabilities into one instrument expands in-situ nano-scale characterization of low dimensional systems.