Heat waves guide heat like light at room temperature in boron arsenide crystals

UCLA scientists observed focused heat propagation through boron arsenide at room temperature, a phenomenon previously limited to cryogenic conditions.

UCLA researchers led by Yongjie Hu demonstrated that heat travels through boron arsenide crystals in wave-like, focused patterns at room temperature—contrasting with random heat diffusion. Using nanoscale temperature mapping, they observed phonon focusing behavior producing sixfold, eightfold, and fourfold heat flow patterns depending on crystal orientation. This effect, detectable across one micrometer distances, arises from boron arsenide’s unusually weak phonon scattering, enabling heat to follow crystal-defined pathways rather than scatter randomly. The discovery—published in *Nature Physics* (2026) with DOI: 10.1038/s41567-026-03335-y—represents the first room-temperature observation of quantum phonon focusing, previously confined to cryogenic systems.

The breakthrough hinges on boron arsenide’s atomic structure, which minimizes phonon scattering and allows wave-like heat transport. This mechanism could enable more efficient thermal management in electronics and industrial systems where heat waste currently drains energy. For practical applications, it reduces energy loss in heat-conduction systems without requiring extreme cooling.

This work advances energy efficiency in heat management but remains limited to nanoscale observations and specific crystal structures. Commercial scalability for broader use is unproven, and the quantum effects observed may not extend beyond micrometer scales. Next steps include testing boron arsenide’s potential in real-world thermal systems while addressing material constraints for wider adoption.

Source: ScienceDaily