Discovery of Record-Setting Thermal Conductor
A UCLA-led, multi-institution research team has identified a metallic material exhibiting the highest thermal conductivity ever measured among metals. This discovery challenges prior assumptions regarding heat transport limits in metallic materials.
The study, published in Science, was led by Yongjie Hu, a professor of mechanical and aerospace engineering at the UCLA Samueli School of Engineering. The team reported that metallic theta-phase tantalum nitride conducts heat approximately three times more efficiently than copper or silver, which are currently considered the best conventional heat-conducting metals.
Material Performance and Significance
Thermal conductivity refers to a material's efficiency in carrying heat. Materials with high thermal conductivity are crucial for mitigating localized hotspots in electronic devices, where overheating can restrict performance, reliability, and energy efficiency. While copper currently dominates the global heat-sink market with a thermal conductivity of about 400 watts per meter-kelvin, the UCLA-led team found theta-phase tantalum nitride to possess an ultrahigh thermal conductivity of approximately 1,100 W/mK. This establishes a new benchmark for metallic materials.
Professor Hu stated that rapid advancements in AI technologies are escalating heat-dissipation demands, pushing conventional metals like copper to their performance limits. He suggested that theta-phase tantalum nitride could offer a superior alternative for achieving higher thermal conductivity and may assist in designing next-generation thermal materials.
Mechanism and Future Applications
For over a century, copper and silver have represented the upper limit of thermal conductivity in metals. In metallic materials, heat is carried by electrons and atomic vibrations (phonons). Strong interactions between these components have historically limited heat flow efficiency. The UCLA discovery indicates that this benchmark can be surpassed.
Theoretical modeling proposed that theta-phase tantalum nitride's unique atomic structure, with tantalum atoms interspersed with nitrogen atoms in a hexagonal pattern, could facilitate unusually efficient heat transport. The team validated the material's performance using techniques such as synchrotron-based X-ray scattering and ultrafast optical spectroscopy, which revealed extremely weak electron–phonon interactions enabling more efficient heat flow than in traditional metals.
Beyond microelectronics and AI hardware, the researchers anticipate the discovery could benefit various technologies increasingly affected by heat, including data centers, aerospace systems, and emerging quantum platforms.
Research Team and Funding
The study's co-lead authors include Suixuan Li, Chuanjin Su, and Zihao Qin, all graduate students from Hu's H-Lab at UCLA Samueli. Additional contributors were from Argonne National Laboratory, Lawrence Berkeley National Laboratory, Tohoku University, and UC Irvine Materials Research Institute.
The research received partial funding from the U.S. Department of Energy and the National Science Foundation.