Carefully engineered metamaterials boost heat transfer between objects by as much as four times, according to a new study.

Led by Carnegie Mellon University, researchers have been able to confirm that heat transfer can be actively designed and enhanced.

At the core of the discovery is a phenomenon called near-field radiative heat transfer. When two objects are brought extremely close together – just a few hundred nanometers apart – heat doesn’t simply radiate away in the usual sense. Instead, it can tunnel across the gap through electromagnetic waves, dramatically increasing how much energy flows between them.

While this effect has been known about for years, scientists haven’t been able to show it experimentally. Using metamaterials, this new study has been able to.

“Unlike conventional materials, metamaterials are built with tiny, repeating patterns that interact with energy in precise ways,” said Sheng Shen, a professor of mechanical engineering at Carnegie Mellon University and senior author of the study. 

“We patterned microscopic gold structures on to thin membranes and positioned them face-to-face across a nanoscale gap. This increased heat transfer by as much as four times compared to similar setups without metamaterials which is far beyond what traditional physics would predict at larger distances.” 

The gold structures interact with naturally occurring energy waves in the material, known as surface phonon polaritons, creating a resonance effect. These coupled vibrations allow energy to move more freely and efficiently across the gap.

“It’s a cooperative effect. The structures and the material amplify each other,” said Shen.

While the study proves the theory, it remains at nanoscale in the laboratory, but the researchers say that in the future it could have implications in many industries. 

For instance, in the design of electronic devices where managing heat is a significant challenge, the ability to precisely control how heat flows could lead to new cooling strategies for chips and high-performance systems.

There are also implications for energy. It could enhance the process of converting heat into electricity in PV systems, making them more practical.

“If heat can be engineered with the same precision as electricity or light, it may open the door to a new class of technologies built not just to withstand heat, but to harness it,” said Shen.

Their study – ‘Metamaterial-enhanced near-field radiative heat transfer’ – has been published in the journal Nature.