Photo: Søren Kjeldgaard

Kristian Sommer Thygesen receives EliteForsk Prize

Micro and nanotechnology Materials Quantum theory and atomic physics Computer calculations
Professor Kristian Sommer Thygesen from DTU Physics is among this year’s recipients of the EliteForsk Prize, which he receives for his research in two-dimensional materials. Two other DTU researchers receive EliteForsk travel grants.

Research in new materials has developed rapidly in the past 15 years. It started in 2004, when two British researchers succeeded in isolating graphene—a single-layer atom material. The existence of this material had long been known theoretically, but it remained unusable until it was isolated.

The same applies to the materials in which Professor Kristian Sommer Thygesen from DTU Physics is conducting research. He works with the thousands of other single-layer—and therefore two-dimensional—atom materials that have emerged since then. In recent years, he has built up the world’s largest library of two-dimensional materials—in the region of 4,000 at the time of writing.

It is one of the reasons why he received the EliteForsk Prize on 28 February.

It is also highlighted in the nomination that Kristian Sommer Thygesen has published more than 150 scientific articles, has been cited by other researchers 8,000 times, and has received a large number of grants, including an ERC Consolidator Grant in 2018. The prize is of EUR 161,000 (DKK 1.2 million), of which EUR 27,000 (DKK 200,000) is given as a personal honorary award, while one million goes to research.

Hypothetical materials
Many of the materials that Kristian Sommer Thygesen works with do not exist. They are hypothetical—just as graphene was until 2004—and only exist in computerized form.

However, he finds that about 1,000 of them can be produced and may find applications in fields such as electronics, batteries, and solar cells, catalysis for production of sustainable energy, and in components which can be used in quantum computers.

“Things have been turned somewhat upside down in the past 15 years. Previously, theoretical physicists like me were chasing those who invented new materials and trying to understand why they worked as they did. Now, we’re more equal, because we have the opportunity to study materials that don’t even exist yet and to render probable in advance what they may be used for,” says Kristian Sommer Thygesen.

It requires huge computational power to calculate quantum mechanical properties in thousands of materials, and the calculations are therefore performed on one of DTU’s supercomputers, Niflheim.

Already known two-dimensional materials are used as a basis, and one atom is then ‘replaced’ with a similar atom from the periodic table. The result is thousands of potential structures. The stability of these new materials—i.e. whether they can in any way exist in the real world—is then calculated. If they can, their thermodynamic, elastic, electronic, and optical properties are then calculated.

Finally, the materials which can—to advantage—be combined can then be studied. Stacking two-dimensional materials makes it possible potentially to manage properties such as the capacity to conduct current or light. And this knowledge can be extremely valuable to a researcher who is—for example—trying to develop flexible, transparent, or more efficient solar cells.

“Computers have become so fast and the methods so accurate that we can make calculations of the properties of these materials in the computer with an accuracy comparable to that achieved in a laboratory. And—mind you—we can do it much faster. It’s a huge advantage—and a major step forward—because it means that the researchers who are to develop the new technologies can save a lot of time and focus exclusively on the materials that can potentially be used for something,” says Kristian Sommer Thygesen.

CV

Kristian Sommer Thygesen is 42 years old and is a Master of Science in Engineering (MSc Eng).

He received his PhD degree in 2005 from DTU Physics, where he is now a Professor and Head of Section.

In 2017, he received a Dr.Techn. degree for his thesis on two-dimensional materials.

He has given more than 70 invited lectures at conferences and summer schools.

He is an active and committed lecturer and has supervised a large number of students, including 14 PhD students.