A sequence showing how thermal energy,
carried by electrons, spreads through theta-phase tantalum nitride after the
metallic material is struck by a pulse of light, from 0.1 to 10 picoseconds.
Credit: H-Lab / UCLA
A UCLA-led, multi-institution
research team has discovered a metallic material with the highest thermal
conductivity measured among metals, challenging long-standing assumptions about
the limits of heat transport in metallic materials.
Published in Science, the study 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 nearly three times more efficiently than copper
or silver, the best conventional heat-conducting metals.
Why thermal conductivity matters in electronics
Thermal conductivity describes how
efficiently a material can carry heat. Materials with high thermal conductivity
are essential for removing localized hotspots in electronic devices, where
overheating limits performance, reliability and energy efficiency. Copper
currently dominates the global heat-sink market, accounting for roughly 30% of
commercial thermal-management materials, with a thermal conductivity of about
400 watts per meter-kelvin.
The UCLA-led team found that
metallic theta-phase tantalum nitride, in contrast, has an ultrahigh thermal
conductivity of approximately 1,100 W/mK, setting a new benchmark for metallic
materials and redefining what is possible for heat transport in metals.
Implications for next-generation technologies
"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," said Hu, who is also a member of the California
NanoSystems Institute at UCLA. "Our research shows that theta-phase
tantalum nitride could be a fundamentally new and superior alternative for
achieving higher thermal conductivity and may help guide the design of
next-generation thermal materials."
For more than a century, copper and
silver have represented the upper bound of thermal conductivity among metals.
In metallic materials, heat is carried by both free-moving electrons and atomic
vibrations known as phonons. Strong interactions between electrons and phonons
and phonon-phonon interactions have historically limited how efficiently heat
can flow in metals. The UCLA discovery demonstrates that this long-standing
benchmark can be surpassed.
The science behind the discovery
Theoretical modeling suggested that
theta-phase tantalum nitride could exhibit unusually efficient heat transport
due to its unique atomic structure, in which tantalum atoms are interspersed
with nitrogen atoms in a hexagonal pattern. The team confirmed the material's
performance using multiple techniques, including synchrotron-based X-ray
scattering and ultrafast optical spectroscopy. These measurements revealed
extremely weak electron–phonon interactions, enabling heat to flow far more
efficiently than in conventional metals.
Beyond microelectronics and AI
hardware, the researchers say the discovery could impact a wide range of
technologies increasingly limited by heat, including data centers, aerospace
systems and emerging quantum platforms.
A leading researcher in electronics
thermal management, Hu pioneered the experimental discovery of boron
arsenide, another
high-thermal-conductivity semiconductor material, in 2018. His group has since
demonstrated high-performance thermal interfaces and gallium nitride devices integrating boron arsenide for
cooling, highlighting
the material's promise for next-generation semiconductor technologies.
Provided by University of California, Los Angeles
by University of California, Los Angeles
edited
by Stephanie
Baum, reviewed by Robert Egan
Source: Newly
discovered metallic material with record thermal conductivity upends
assumptions about heat transport limits
