Faces of the IMPRS: Felix Küster

“The microscope is my favorite instrument, it opens a door to worlds we could never see.”

What is the topic of your research/doctoral thesis?

During my time at the MPI, I specialized in investigating new and technically promising materials such as superconductors and topological insulators on their surface using scanning tunnelling microscopy at temperatures close to absolute zero. My doctoral thesis was primarily concerned with researching artificial magnetic structures, generated "atom by atom", on the surface of a superconductor - a quantum mechanical system for which exotic, so-called Majorana states are expected. Control over such states should enable the construction of the next generation of quantum computers in the future.

What was the most exciting thing about the topic?

The topic itself is at the forefront of current research and of fundamental physical and technological interest. I was very lucky to have Paolo Sessi as project manager, who allowed me for an easy entry to this research. With his experience, he enabled us not only to carry out extremely challenging experimental measurements, but also to collaborate with leading theoretical scientists in the field, which made possible to compete with world-leading research groups for the most influential publications.
From a physics point of view, it was absolutely fascinating for me to be able to move individual atoms on the surface of a single crystal with ultimate precision and in turn to build up crystal lattices with controllable electron states. It's like playing Lego with the smallest stable building blocks in our world, creating constructs with properties that may never have been observed before.

What is the best memory of your Ph.D. time?

The favorite memories are events like the Long Night of Science or visits from school groups where I could see the curiosity, fascination and amazement of people looking at our experiments. It gives me the positive feeling that science is of great value and interest not only technologically, but also socially and culturally.

How was the MPI / IMPRS able to support you with your Ph.D.?

I had the opportunity to do research at an institute with great scientific facilities and almost unlimited financial resources and only had to ask to be allowed to attend international conferences.
However, by far the greatest support I had was from Paolo Sessi, who, with his many years of experience in both the most sophisticated techniques of scanning tunnelling microscopy and the publication of measurement data, was always there to help and advise me. Without him, my Ph.D. time would not have been nearly as successful.

What was the biggest challenge during the Ph.D. phase?

According to the motto "Science never sleeps", there is always a lot to do. You could take measurements around the clock and organize your daily routine around the instrument measurement times. Family life with small children is often difficult to reconcile with this, so the biggest challenge for me was to maintain a good work-life balance.