Prof. Stefan Müllegger (43) is from Bad Ischl, Germany and heads the nano-spectroscopy group at the Institute of Semiconductor and Solid-State Physics. Today he talks about how many molecules are needed for a measurement and his latest hobby.

What is your area of research?
Prof. Stefan Müllegger: I conduct physics experiments using single molecules which means I use a modified scanning tunneling microscope under very idealized experimental conditions (single crystal substrate, ultra-high vacuum and low temperature of approximately 8 Kelvin).

What do you find particularly fascinating about this area?
Prof. Stefan Müllegger: Compared to the coronavirus, the molecules I work with are a 100-times smaller. I find it fascinating that despite being so incredibly tiny, I can make it visible and even measure its properties.

Why is this research even necessary, meaning how will it improve our lives?
Prof. Stefan Müllegger: From a practical viewpoint, it’s about an enormous increase in sensitivity by a factor of 1,000,000,000 compared to conventional measuring methods. Ultimately, a single sample of a molecule would suffice to be a reliable determination.

Why should students take your classes?
Prof. Stefan Müllegger: I spend a lot of time holding discussions with my students and I spend time with them, often conduct experiments in the laboratory. This is how I share my experiences with them directly and always learn something new myself.

What are you currently working on?
Prof. Stefan Müllegger: I am currently working on "single atom radio frequency fingerprinting" which focuses on making certain single molecule physical properties measurable, such as the spin state or mechanical natural frequencies. If successful, we could determine what kind of molecule is involved and would just need a single copy of it.

What are your hobbies?
Prof. Stefan Müllegger: Lately I have been enjoying cooking very much.

What else do you want to do or achieve in your life?
Prof. Stefan Müllegger: That remains my little secret. ;-)