Researchers at UCLA have observed phonons moving in focused, ray-like paths through boron arsenide at room temperature, showing that a quantum heat-transport effect previously associated with very cold conditions can persist in a warmer environment. The phrase quantum heat waves room temperature describes the result.

UCLA’s Samueli School of Engineering said the team demonstrated phonon focusing at 300 kelvin. Phonons are atomic vibrations that carry heat, and the experiment showed that their paths can be guided by the crystal structure instead of spreading evenly in all directions.

Phys.org reported that the researchers used a nanoscale temperature-mapping technique to see the patterns. Different crystal orientations produced different focusing shapes, including fourfold, sixfold and eightfold structures.

The result is important because heat management is a major challenge for electronic devices. If heat can be directed along controlled paths, engineers may be able to design materials and interfaces that move energy away from sensitive components more precisely.

The reported distances were on the micrometre scale, with the research team saying the behaviour could potentially continue over longer distances in suitable devices. That does not mean a commercial cooling product is ready, because the material, fabrication and integration challenges remain.

The study was published in Nature Physics and builds on earlier work involving boron arsenide. The current finding establishes a physical observation at room temperature; applications in electronics, photonics or quantum systems will require additional engineering and testing.