Slovak Scientists Experimentally Confirmed a Nobel Prize-Winning Theory — and Secured a Highly Prestigious Publication
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They contributed to research that may help break through the "dead end" in microchip development.
In 2016, David Thouless, Duncan Haldane, and Michael Kosterlitz received the Nobel Prize in Physics for their theory describing the mechanism of "topological phase transition in two dimensions." In simple terms, 2D materials change from solid to liquid in a fundamentally different way than, say, ice melting into water.
In 2025, an international team that included scientists based in Slovakia managed to prove that the same mechanism governs the melting of two-dimensional materials with so-called strong covalent bonds — a result significant enough to be published in Science, one of the world's most prestigious scientific journals.
The 2D World
For a long time, it seemed that materials made of a single atomic layer (2D materials) couldn't exist at room temperature — they would be too unstable. In 2004, however, Professor Andre Geim and his colleague Konstantin Novoselov at the University of Manchester successfully isolated a 2D layer using an unexpectedly simple method: they pressed ordinary adhesive tape onto a piece of graphite, peeled it against a silicon substrate, and found under a microscope that a single-atom layer of carbon — graphene — had appeared on the surface. Geim and Novoselov received the Nobel Prize for this in 2010.
2D materials could help advance the development of electronic components, since the dominant silicon-based technology is approaching its physical limits. "The idea is to stack 2D materials into thin layers. Each layer is a different material with different electronic properties, and they can be combined into electronic components," explained Viera Skákalová, one of the researchers involved in the Science study.
The scale of this challenge is illustrated by the progress humanity has already made: in 1958, Jack Kilby and Robert Noyce managed to connect a few transistors on a piece of germanium. Today's microchips contain tens to hundreds of billions of transistors.
"2D materials won't completely replace silicon technology, but new principles and new electronics architectures may emerge, used where silicon falls short. 2D materials are, for example, flexible and can be very durable," Skákalová added.
A Slovak 2D Breakthrough
Associate Professor Skákalová spent 20 years at the Faculty of Chemical and Food Technology at the Slovak University of Technology, 12 years at the Max Planck Institute in Stuttgart, eight years at the University of Vienna, and has also worked at the Weizmann Institute in Israel. She currently conducts research at the Institute of Electrical Engineering of the Slovak Academy of Sciences (SAS), and is also managing director of Danubia NanoTech, which developed a method for producing a specific 2D material — silver iodide — that previously didn't exist in stable form. "Together with Peter Kotrusz, we managed to stabilize it by creating it directly between two layers of graphene," she explained.
Long hours of observation followed under a state-of-the-art electron microscope at the University of Vienna. "We started heating it. Melting a two-dimensional substance is far from trivial — an atom has almost nowhere to move," Skákalová said.
"It wasn't clear how a liquid forms. We managed to reveal one of the possible ways the process is triggered. Below 1,000°C, the material maintained its regular hexagonal structure. Then the predicted 'topological defects' began to form — without significant atomic displacement, just by the rotation of a bond. But just 15 degrees more was enough for the material to melt," she described. The research was supported through the EU NextGenerationEU Recovery and Resilience Plan for Slovakia.
The Science Paper
The Slovak researchers and their colleagues from Vienna experimentally confirmed a theory that won the Nobel Prize in 2016, adding new details to the mechanism of 2D material melting. "We were the first to demonstrate the theory for a covalently bonded material. We showed that even very strong covalent bonds behave as the theory predicts — and moreover, that the phase arising from defects persists for only about 25 degrees before a conventional phase transition follows," Skákalová noted.
The reward was publication in Science, with an unusually rigorous review — four referees instead of the standard two. Additional rounds of experiments followed, evaluated using a neural network, with the validity of that method also needing to be proven. "We analyzed hundreds of images before our conclusions were accepted. It took months, but by Science standards it was published relatively quickly," she concluded.
Fundamental Science
The work has no direct practical application yet — it primarily advances understanding of basic phenomena in new materials. But that is the nature of science. "Sometimes tens of thousands of experiments are needed before you find a combination that's usable," said Michaela Sojková, another SAS researcher working on 2D materials.
One particularly valuable finding: after the melted silver iodide is cooled, it returns to its original form. This stability is an important result in itself — and may prove useful in future applications.