Copper moves the world’s heat. For more than a century it has been recognized as one of the best heat conductors in nature, and this property made copper the go-to choice to cool electronics, industrial equipment, data centers and power systems. But there’s a new, record-breakingly cool metal in town.

As reported in Science, a metallic material called θ-phase tantalum nitride achieved a thermal conductivity of about 1,110 watts per meter-kelvin—about three times higher than copper’s 400 watts per meter-kelvin. And it works in a way scientists have never seen before. “Our result breaks the historic ceiling for heat transport in metallic materials,” says senior author Yongjie Hu, a physicist and engineer at the University of California, Los Angeles. “Given [this conductor’s] superior performance, it has the potential to complement or even replace copper.”

Similar to the way pure carbon can form diamonds, graphene, or other structures, tantalum nitride exists in multiple forms with very different properties. Scientists have known about some of those forms for decades, but until now no one had studied the specific configuration Hu and his colleagues focused on, in which the material’s atoms are arranged in a continuous, highly ordered crystal lattice. In this structure, the researchers found that both electrons and packets of vibrational energy called phonons, which carry heat and sound, encountered less resistance compared with conventional metals, letting them conduct heat better.

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The material also revealed a previously unexplored strategy to boost metallic heat conduction. In ordinary metals, phonons are frequently disrupted by collisions with one another and with electrons, reducing their ability to dissipate heat. In the form of tantalum nitride that Hu and his colleagues studied, the atomic structure of the crystal lattice lets phonons travel unusually long distances with minimal interference. This discovery provides a new direction for scientists designing next-generation thermal materials, Hu says.

The study’s findings “are both exceptional and conceptually important,” says Xiaojia Wang, a mechanical engineer at the University of Minnesota who was not involved in the research. The team rigorously verified its measurements, which suggests they are robust, she says, and if the material can be manufactured at scale, it could have a “substantial impact” on thermal management for electronics, data centers and energy systems.

Hu adds that θ-phase tantalum nitride could be especially valuable as artificial intelligence gains even more widespread use and heat dissipation becomes a data-center bottleneck. For materials scientists, the work could also provide inspiration to challenge other long-standing constraints. “Do we truly understand where the real limits lie, or do the boundaries assumed for decades to be fundamental simply reflect our current tools and understanding?” Hu asks. “Now that the record has been broken for heat conduction, it makes us rethink whether other assumed boundaries in materials physics could also be broken.”