UCLA researchers achieve room-temperature heat steering using boron arsenide crystal

UCLA scientists have demonstrated that heat can travel in focused, ray-like paths at ambient conditions by using boron arsenide, suggesting new ways to cool advanced electronics.

Researchers at UCLA’s Samueli School of Engineering have experimentally observed phonon focusing in the semiconductor boron arsenide at room temperature, allowing heat to travel in narrow, ray-like trajectories rather than diffusing isotropically. By employing a novel nanoscale temperature-mapping technique, the team visualized distinct patterns that aligned with specific crystal planes, showing sixfold, eightfold and fourfold symmetries that persisted over micrometer distances.

Lead scientist Yongjie Hu explained that this wave-based transport mirrors optical fiber guidance and could enable precise thermal routing in advanced electronics, AI hardware, aerospace systems and quantum information platforms. The work builds on Hu’s earlier discovery of boron arsenide and its unusually weak phonon scattering, which sustains coherent heat flow despite ambient scattering. Co-authors Man Li, Huan Wu, Zihao Qin, Chuanjin Su and Huu Duy Nguyen contributed, with funding from the U.S. Department of Energy, the National Science Foundation, the National Institute of General Medical Sciences and a private gift fund. The study appears in Nature Physics.