Affiliation: Max-Planck-Institute for Solid State Research, Germany

Research Field: Quantum Limits in Scanning Tunneling Microscopy, Superconductivity

Experimental Details of a Dilution Fridge STM

Reaching lowest temperatures in scanning tunneling microscopy (STM) requires combining the microscope with a dilution refrigerator, which triggers interesting technical. Most importantly, a dilution fridge is not a quiet piece of equipment, but STM requires the lowest noise possible. Even measuring temperature becomes a non-trivial problem. Also, the choice of materials that perform well at lowest temperatures, but are at the same time suitable for sample preparation at high temperatures is very limited. Furthermore, modeling the tunnel junction to interpret the experimental data at mK temperatures requires to go beyond the tunnel junction itself to macroscopic scales. The lower the temperature, the more the experiment becomes part of the experiment. I will discuss the challenges of building a mK-STM and interpreting the experimental data, which in the end leads to a much better understanding of the tunneling process as a whole.