The JT-STM marks SPECS' latest significant achievement in UHV scanning probe microscopy - simple handling, unprecedented stability, and an extremely long operating time without interruption

Features

• Base temperature: 1 K (optional <500 mK)
• LHe hold time: >100 hours
• LN₂ time: >100 hours
• Extreme stability and resolution
• Nanonis control system

Product Description

Following the design of Prof. Wulf Wulfhekel, the cryostat concept is based on a Joule-Thomson stage below a LHe bath cryostat with vapor-cooled shields and a surrounding LN₂ vessel, all in a UHV environment. The consumption of LHe and LN₂ in the entire cryostat is extremely low. This reduces cost and vibration and allows automated experiments to be run over very long time periods. The hold time for experiments is more than 4 days.

The Joule-Thomson stage below the LHe bath cools the STM down to 1K using ⁴He. The handling of the gas flow through the Joule-Thomson stage is very simple. Helium gas from a cylinder is pre-cooled to 4K and expanded in a long capillary to a pressure of a few millibars. Liquefied helium is collected in the Joule-Thomson vessel.

The STM is extremely stable mechanically at all temperatures and allows positioning of the tip above an atom for extended periods. The thermal broadening of the Fermi edge is reduced significantly compared with what is typically observed at 4K.

The JT-STM in conjunction with the Nanonis control system exploits both of these advantages to the fullest, and is therefore especially suited to all kinds of tunneling spectroscopy experiments.

³He Upgrade Option
The Joule-Thomson stage can also be operated with ³He. This option can be installed without modifying the UHV system. About 10 liters of ³He gas are pumped in a closed cycle. With ³He the temperature can be reduced to 500 mK.

Magnet Option or Upgrade
A superconducting magnet can be installed upon request or added later to apply magnetic fields up to 3 Tesla normal to the sample. The split coil magnet is mounted in UHV on the 4K radiation shield. A precision power supply ensures automated and safe operation. Magnet operation does not increase helium consumption since the magnet is powered through high-TC superconducting supply leads.

KolibriSensor® AFM Upgrade
SPECS is currently developing an option to upgrade the JT-STM for non-contact AFM at sub-angstrom amplitudes based on KolibriSensor^® technology. The KolibriSensor^® features a separately contacted metallic tip for STM mode scanning or electrical tip access in nc-AFM mode.

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