Data center servers, powerful smartphones, and your computer's motherboard have one thing in common. When these devices get too hot, their performance takes a hit, and we can't have that. That's why copper is used to manufacture them: this metal has high thermal conductivity, which means it can efficiently carry heat and dissipate it across its surface.

Now, copper is already pretty good at what it does. With a thermal conductivity of approximately 401 W/mK at room temperature, it's second only to silver by a wee bit, while being a lot less expensive to procure. But aerospace engineers at University of California Los Angeles (UCLA) have discovered a material that blows those two out of the water with nearly thrice the thermal conductivity.

Metallic theta-phase tantalum nitride exhibits an ultrahigh thermal conductivity of 1,100 W/mK, which means it's way more efficient at transporting heat than copper and silver. Their conductivity is limited by the strong interactions between free-moving electrons and atomic vibrations called phonons.

That name just rolls off the tongue, doesn't it? It refers to a specific crystal structure of this metallic compound which has certain properties – similar to how carbon can be found in the form of soft graphite, and also as hard diamond.

Using molecular structure analysis techniques like synchrotron-based X-ray scattering and ultrafast optical spectroscopy, the researchers found unusually weak electron-phonon interactions in this specific configuration of tantalum nitride. This allows for super-efficient heat flow through the material with a lot less resistance, vastly exceeding what we see with copper and silver. The findings were published in the journal Science this month.

"As AI technologies advance rapidly, heat-dissipation demands are pushing conventional metals like copper to their performance limits, and the heavy global reliance on copper in chips and AI accelerators is becoming a critical concern," explained Yongjie Hu, a professor at the UCLA Samueli School of Engineering who led the study.

This metallic material could prove to be a desirable alternative to copper in heat sinks – not just for computers and AI hardware, but also for aerospace systems and quantum computers that need to constantly run cool.

Source: UCLA