At home in a two-dimensional world

Märta Tschudin studies magnetism at the atomic level at the University of Basel

Female scientists have been gaining more and more ground in the Department of Physics at the Uni-versity of Basel in recent years. One of them is Märta Tschudin. As part of her doctoral thesis at the Quantum Sensing Lab, she is researching the extremely weak magnetic fields of ultra-thin layers of material that consist of only a single atomic layer.

Quantum physicist Märta Tschudin from Basel.
Image: Privat

In 2017, the Spanish physicist Pablo Jarillo-Herrero made a sensational discovery at the renowned Massachusetts Institute of Technology (MIT) in Boston (USA): He was able to show that the carbon-containing material graphene is superconducting, i.e. it conducts electricity at low temperatures without resistance. For his experiments, he used so-called monolayers of carbon atoms. These are ultra-thin layers of material in which atoms are only arranged next to each other, but not on top of each other, and are therefore referred to as 'two-dimensional'. In 2020, Jarillo-Herrero and two colleagues received the Wolf Prize, one of the most important awards after the Nobel Prize, for their discovery.

Detour to MIT in Boston

Physics research with monolayers - also called 'physics in 2D' - is in vogue, and it has long since arrived at the University of Basel. One researcher who brought the knowledge to Basel is Märta Tschudin. In 2019, the Basel native began her doctoral studies, and the first thing she did was go to MIT to work with Pablo Jarillo-Herrero for just under a year. There she learned how to make magnetic samples from monolayers. With this knowledge, researchers at the University of Basel can now produce such samples themselves and investigate them using a method that had been significantly developed at the University of Basel a few years earlier.

For our video conference, Märta Tschudin has chosen a place on the second floor of the physics building at the University of Basel. The windows are covered with protective film so that daylight does not disturb the experiments. In the background, a laser device can be seen that is used to study the monolayers. The 26-year-old researcher speaks Basel dialect. But when she talks about her work, she stumbles over English words every now and then. " ‚Switch‘, how do you say in German?" she then asks, looking for the German equivalent. The language confusion is not surprising, because Märta Tschudin's working language is English. She is part of the 20-member international research group led by Prof. Patrick Maletinsky, who is also supervising her doctoral thesis.

Basel is first choice

Märta Tschudin had already studied physics at the University of Basel and written her Master's thesis under Patrick Maletinsky. She would have liked to go abroad for her doctorate. But Basel is a world leader in the study of monolayers. So, she decided to stay here, supplemented by a visit to MIT for just under a year. Even so, she does not lack international experience: for her Master's thesis, the young researcher spent six months in Montreal (Canada) with Prof. Lily Childress, professor at McGill University.

Now she's back in Basel. Here, Märta Tschudin is investigating magnetic phenomena in monolayers with the help of so-called NV centres. NV centres are an investigation method co-developed by Patrick Maletinsky, in which a magnetic field sensor (the NV centre) in a diamond tip scans a material and thus measures the magnetic field on an atomic scale. The researchers around Maletinsky focus their investigations on the material group of chromium trihalides (CrX3, where X stands for chlorine, bromine or iodine). This family of two-dimensional magnets was only recently discovered. Magnetic states that can be observed on the chromium atoms could one day help in the construction of a quantum computer in the future. Such practical applications, however, are not the driving force for Märta Tschudin. "My work is fundamental research, my first motivation is curiosity," she says.

Female role models

The young researcher finds the University of Basel an ideal environment. Expertise from various fields of quantum physics is gathered here. But Märta Tschudin is also motivated by the fact that more and more women have been working in the physics department in recent years. Among them also female professors: Jelena Klinovaja, Ilaria Zardo, and most recently Andrea Hofmann. "It is helpful to have female role models," says Märta Tschudin. "When both genders are represented in a research group, it's very good for inventiveness and group dynamics." Märta Tschudin appreciated that she received a women's scholarship from the Swiss National Science Foundation during her Master's studies: "With this financial support, I was able to fully concentrate on my studies and it gave me the push to stay in science after my Master's thesis."

When Märta Tschudin attended high school, she chose to focus on mathematics and physics. There were five girls in the class of just over 20 students. The fact that she was in the minority did not prevent her from discovering a passion for physics: "The subject was just great fun. In physics, you work with experiments. So, the discipline also corresponds to my inclination to be creative. When I work in experimental physics today, it's an optimal combination of creativity and logical thinking for me."

Author: Benedikt Vogel

Portrait #9 of Women in science in the fields of MAP (2021)

  • Märta Tschudin (here together with a fellow student) wrote part of her master's thesis at McGill University in Montreal (Canada).
  • At the beginning of her doctoral thesis, Märta Tschudin spent almost a year in Boston at the Massachusetts Institute of Technology (MIT).
  • Schematic representation of NV magnetometry: The magnetic field sensor (NV center) is located in a diamond tip (top of picture). The sensor scans the material sample (below) using laser light and measures the magnetic field of the material layer, which is only a few atomic layers thick. The measurement method works at 4 Kelvin, i.e. close to absolute zero.
  • Quantum physicist Märta Tschudin from Basel.
  • Märta Tschudin (here together with a fellow student) wrote part of her master's thesis at McGill University in Montreal (Canada).Image: Privat1/4
  • At the beginning of her doctoral thesis, Märta Tschudin spent almost a year in Boston at the Massachusetts Institute of Technology (MIT).Image: Privat2/4
  • Schematic representation of NV magnetometry: The magnetic field sensor (NV center) is located in a diamond tip (top of picture). The sensor scans the material sample (below) using laser light and measures the magnetic field of the material layer, which is only a few atomic layers thick. The measurement method works at 4 Kelvin, i.e. close to absolute zero.Image: Quantum Sensing Group, Universität Basel3/4
  • Quantum physicist Märta Tschudin from Basel.Image: Privat4/4
Märta Tschudin: Mit kräftigen Griffen

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