Glass found to conduct heat as well: a counterintuitive discovery by the CSIC that opens up new avenues for electronics

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The advancement of new electronic and quantum technologies runs into a bottleneck: heat. A significant portion of the energy consumed by these systems is spent solely on cooling them. For this reason, researchers around the world are working to find a solution—a solution that appears to lie where no one was looking: in a material that acts as a thermal insulator—glass.

An international study, co-led by the Madrid Institute of Materials Science —part of the Spanish National Research Council (CSIC)—and the University of Colorado Boulder (USA), with the participation of the Autonomous University of Madrid (UAM), has discovered that glass, at the atomic level—specifically when stretched into a strand only one atom thick—becomes an exceptional heat conductor. It reaches 40% of the quantum limit, the absolute maximum permitted by physics. In other words, glass allows for a heat flow “far greater than anything previously measured in an insulator of this size,” explains Guilherme Vilhena, a CSIC researcher at the Institute of Materials Science of Madrid (ICMM) and co-lead author of the study, which has just been published in the journal Nature Nanotechnology.

“We have discovered that glass transports ten times more heat than any other electrical insulator measured at this scale. It is a record, at least for now,” adds Pablo Martínez, a predoctoral researcher at ICMM-CSIC and the UAM, and one of the study’s lead authors. “Until now, heat transport in insulators at these atomic scales was limited to values ​​ten times lower,” he emphasizes.

The work combines the theoretical approach of the ICMM-CSIC and Juan Carlos Cuevas’s group at the UAM with the experimental approach of Longji Cui at the University of Colorado Boulder, in whose laboratories the experiments were conducted. The researchers explain that a “physical system that was so transparent to the passage of heat” had never been encountered before.

Moreover, the point is that this involves “the very system you would least expect, given that it is a thermal insulator,” adds Óscar Mateos, a predoctoral researcher at the ICMM-CSIC and the UAM—who, incidentally, is currently on a research stay at the University of Colorado Boulder. Glass is the material we turn to for retaining heat: think of double-glazed windows, oven doors, or thermos flasks. The ‘surprise’ came when it was discovered that, by stretching this same glass into a strand only one atom thick, it behaves in the opposite way, allowing heat to pass through with unprecedented efficiency.

Reference:

Sai C. Yelishala, Yunxuan Zhu, P. M. Martinez, O. Mateos-Lopez, Wan Xiong, Dishan Chooi, Sophie Kimura, Juan Carlos Cuevas, J. G. Vilhena*, Longji Cui*. Thermal conductance of atomic-scale glass reaches 40% of quantum limit. Nature Nanotechnology (2026). DOI: 10.1038/s41565-026-02308-9.