Discovery of 'slow' electrons in 2D material could lead to new memory device

edited by Gaby Clark , reviewed by Robert Egan

This article has been reviewed according to Science X's editorial process and policies . Editors have highlighted the following attributes while ensuring the content's credibility:

Add as preferred source Over the last decade, researchers have developed two-dimensional materials with fascinating quantum effects that could be harnessed for next-generation technologies.

Such materials have shown superconductivity—conducting electricity without energy loss—and charge orders, where electrons arrange in frozen patterns rather than moving freely in the material.

At the University of Chicago Pritzker School of Molecular Engineering (UChicago PME), a research team discovered that one such material, Fe 5 GeTe 2 , exhibits a charge-ordered state in which electrons move collectively and unusually slowly while remaining quantum coherent.

The research, published in Science Advances and conducted in the lab of assistant professor Shuolong Yang, rewrites current knowledge of the material and could unlock new technological applications.

"This is a fundamental discovery that deviates from theoretical predictions," Yang said. "We now have to go back and think about the magnetic interactions of this material from scratch, but it also leads to new possibilities in using this material for new kinds of memory devices."

Discovered seven years ago, Fe 5 GeTe 2 is part of a class of materials known as van der Waals magnets. Their atomically thin layers could enable new kinds of memory technologies, with advantages over those based on conventional magnetic materials.

Yang and his team, including postdoctoral scholars Gabriele Berruto and Qiang Gao, studied the material with angle-resolved photoemission spectroscopy (ARPES), which uses photons to eject electrons from a material's surface. That gives scientists the ability to observe the material's electronic structure and magnetic states.

A flat band is a strange phenomenon in which the electrons within a material don't move as fast as they should. In fact, they move very slowly, all together.

"We're not measuring one electron," Yang said. "We're measuring the interaction of thousands or millions of electrons, and they are all moving together in a coherent way. That's a quantum many-body phenomenon, and it's actually a very weird thing."

Yang likens it to a waterfall: When the slope is steep, the water flows faster. But when the slope is shallow, the water flows slower. The finding of these very slow electrons changes how scientists and engineers view the material, which has many different structural arrangements of atoms within it.

"From a scientific perspective, it suggests that the magnetic interactions within the material are totally different from what theory predicts," Berruto said.

From a technological point of view, the phenomenon shows that the material's different magnetic states could be used to encode information in a memory storage system. In fact, Yang and the team are currently working to switch between this quantum many-body phase and other phases using a microfocused laser, showing that this switching is possible and could be used in a memory device.

While most of these quantum phenomena can only be observed and harnessed at extremely cold temperatures, the team found this response to be coherent up to 100 degrees above absolute zero. Still below room temperature, but very promising compared with analogous materials.

"If we eventually want to use it in a memory device, it needs to work at room temperature," said Gao, who is now a research scientist at Lawrence Berkeley National Laboratory.

Next, the team will continue working to see if they can find the same properties if they exfoliate the material down to a single atomic layer.

This paper was one of the final research publications of Peter Littlewood, a distinguished physicist at UChicago who died on June 15.

"He was a great theoretical physicist and a leader of quantum materials research at UChicago," Yang said. "We dedicate this paper to him."

Other authors on the paper include Khanh Duy Nguyen, Chaowei Hu, Paul Malinowski, Haoran Lin, Beomjoon Goh, Bo Gyu Jang, Xiaodong Xu and Jiun-Haw Chu.

Qiang Gao et al, Interaction-driven flat band and charge order in Fe 5 GeTe 2 , Science Advances (2026). DOI: 10.1126/sciadv.aeg5930

MA in English, copy editor since 2021 with experience in higher education and health content. Dedicated to trustworthy science news. Full profile →

Bachelor's in mathematical biology, Master's in creative writing. Well-traveled with unique perspectives on science and language. Full profile →

Indexed and credited by AIPROPX. Originating outlet: Phys.org. Open at source →