Can a small lump of metal be in a quantum state that extends over distant locations? A research team at the University of Vienna answers this question with a resounding yes. In the journal Nature, physicists from the University of Vienna and the University of Duisburg-Essen show that even massive nanoparticles consisting of thousands of sodium atoms follow the rules of quantum mechanics. The experiment is currently one of the best tests of quantum mechanics on a macroscopic scale.
In quantum mechanics, not only light but also matter can behave both as a particle and as a wave. This has already been proven several times for electrons, atoms and small molecules, through diffraction at a double slit or through interference experiments. However, we do not see this in everyday life: marbles, stones and dust particles have a well-defined location and a predictable trajectory; they follow the rules of classical physics.

Scientists at the University of Vienna and Prof. Dr. Klaus Hornberger from the University of Duisburg-Essen have now demonstrated for the first time that the wave nature of matter is also preserved in massive metallic nanoparticles. The scale of the particles is impressive: the clusters have a diameter of around 8 nanometres, which is comparable to the size of modern transistor structures. With a mass of more than 170,000 atomic mass units, they are also more massive than most proteins. Nevertheless, quantum interference can be detected in these nanoparticles.
Original publication: https://doi.org/10.1038/s41586-025-09917-9
In the image: Matter wave in the spotlight: AI-generated interpretation of the wave properties of matter. A blurred cluster composed of many atoms floats in the cone of light. The blur represents a delocalised quantum state: the cluster has no fixed location but is spatially extended as a wave function. Beneath it, a grid spans out, reminiscent of several possible interferometer paths. The cone of light symbolises the measurement process: only when the particle enters the ‘spotlight’ during measurement is the cluster clearly determined at a specific location.

Scientists from Grenoble, Bordeaux and the University of Duisburg-Essen have unlocked fresh understanding of two-dimensional material that could shape tomorrow’s high-performance devices. They have synthesized high-quality Ti₃C₂Cl₂ MXenes, an atomically thin metal carbide with chlorine surface groups, and used cutting-edge techniques to peer deep into how its atoms vibrate and conduct heat.

How lattice vibrations, tiny quantum mechanical ripples called phonons, move through 2D crystals differ from well-explored 3D materials. These vibrations influence everything from thermal conductivity to electrical behavior, but until now, scientists have struggled to measure them accurately in MXenes because of stacking disorder and non-uniform surface terminations.

By carefully growing MXene sheets with uniform chlorine terminations, the team captured exceptionally clear vibrational “fingerprints” using polarized Raman spectroscopy and combined these measurements with theoretical calculations. This revealed how different vibrational modes behave and how they change with temperature giving an unprecedented picture of optical phonon behavior in this 2D material.

In parallel, precise measurements of specific heat and corresponding calculations exposed how MXenes’ heat capacity responds to temperature, uncovering tell-tale signs of their two-dimensional character at very low temperatures which is often hidden in other materials.

Understanding and controlling phonons in MXenes is a key step toward designing faster electronics, better thermoelectric materials, and improved energy-storage systems. This work lays solid scientific groundwork for tuning thermal and vibrational properties in 2D materials, bringing next-generation technologies a step closer.

The authors acknowledge financial support of the Deutsche Forschungsgemeinschaft and the Agence Nationale de la Recherche in the bilateral ANR-DFG project.

Reference:

M. Riabov, M. Vanselow, A. Champagne, et al. Phonon properties of 2D Ti₃C₂Cl₂ MXenes. npj 2D Mater Appl 9, 114 (2025). https://doi.org/10.1038/s41699-025-00625-6

An important decision will soon have to be made for all those finishing school this year: the decision for or against a course of study and the choice of degree program.

The Faculty of Physics at the University of Duisburg-Essen is happy to provide support and information. We will present our Energy Science, Physics and Physics Teacher Training degree programs via video conference on the following dates

• Wednesday, February 25th 2026, 5-6 p.m.
• Saturday, March 28th 2026, 2-3 p.m.

Afterwards, questions can be asked in a relaxed round. Contact persons are at least two students and one full-time lecturer. The students are part of our buddy system. Within the Buddy System, we offer all-round advice for future students before the start of their studies and during the first two semesters. Further information on the Buddy System can be found on the Buddy System homepage and in the flyer.

If you would like to take advantage of this offer (buddy@school digital 2026), please register simply and briefly (at least one week before the desired date) via the online form at https://udue.de/bas26. The offer is of course also available to those who will not be finishing school until the next few years but would like to find out more today.

We look forward to seeing you!