Low-temperature scanning tunneling microscope

The microscope takes advantage of the quantum phenomenon of electron tunneling between the sample and the tip, enabling atomic-resolution observation of sample surfaces. This capability extends to imaging molecular structures, identifying defects, and examining the local density of electronic states through scanning tunneling spectroscopy (STS). Measurements are conducted under ultra-high vacuum conditions (below 1 × 10⁻¹⁰ mbar) in a broad temperature range from approximately 10K to 400K. Its closed-circuit cooling system eliminates the need for liquid helium, facilitating efficient operation. This design allows simultaneous cooling of both the sample and the tip, significantly enhancing resolution and minimizing the effects of thermal noise on the signal.

The microscope is installed in a two-chamber ultra-high vacuum system, allowing for sample preparation processes such as heating, ion bombardment, and adsorbate deposition. It also facilitates additional surface characterization, including chemical composition analysis via Auger electron spectroscopy (AES) and crystallographic order evaluation using low-energy electron diffraction (LEED). These operations are conducted under precise monitoring of the system's residual gas content with a quadrupole mass spectrometer (RGA).