Researcher Accidentally Reveals Intricate Physics of Electron Crystals Theorized in the 1930s

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A University of Maryland researcher studying the optical properties of a two-dimensional material noticed unusual behavior in his sample—turns out, he was looking at vibrations of electron crystals, revealing new insights into these quantum states of matter.

The study was a first in observing the internal dynamics of “Wigner crystals,” semiconductor materials that only realize under limited conditions. The paper was published by You Zhou, an associate professor in the Department of Materials Science and Engineering, for the journal Nature Physics.

"Most work on Wigner crystals has asked a yes-or-no question: is the crystal there? We found ourselves able to answer a different one: what is it actually doing?" said Zhou. "That was not by design. It was a discovery by accident."

Wigner crystals, unlike conventional crystals made of atoms, are formed only by electrons. They are named after Eugene Wigner, the Nobel Laureate physicist who predicted them in 1934. Since then, only a handful of experiments have demonstrated their existence due to their fragile nature. Electron crystallization only occurs at very low temperatures, and with very low electron density, presenting many experimental challenges to realize them. At the same time, due to their fragile nature, conventional experimental techniques are ineffective in studying the properties of such crystals, for example, how they vibrate.

Zhou’s research team, which is focused on studying optical devices and a broad range of physics fundamentals, had started some work in this field several years ago. But it wasn’t until he accidentally recreated Wigner’s crystallization phenomenon that he was able to observe its internal dynamics.

"We were initially puzzled. There were extra peaks in our spectra that we had never seen before, and none of the usual explanations worked," said Zhou. "It took us a while to realize we were watching the electron lattice itself vibrate."

His experiments established a way to detect the phenomenon, using an optical system that measured the crystals’ vibration qualities, known as their “phonon” properties, which are key to understanding how the crystals behave, which informs future applications. Currently, these materials are of interest to the electronics and optical device research communities due to their ability to switch between different states.

Now, he hopes to solve new questions about the rare semiconductor materials, with his team working on ways to use light to switch a material from one state of matter to another at very high speeds.

Media contact: Daniela Benites
Communications Coordinator
dbenites@umd.edu

Published August 24, 2026