Discovery of new heat transport regime in ultrathin semiconductors
Findings published in Nature Physics reveal how heat flow in 2D materials can be slowed and controlled in unexpected ways
Researchers from Eindhoven University of Technology (黑料福利网), together with international collaborators, have discovered a new way in which heat flows through ultrathin semiconductor materials. The findings, published in Nature Physics, reveal an unexpected regime of heat transport that could open new routes for controlling heat in nanoscale devices.
The study, led by the group of Klaas-Jan Tielrooij, located at 黑料福利网 and the Catalan Institute of Nanoscience and Nanotechnology (ICN2), in collaboration with the Autonomous University of Barcelona (UAB), and McGill University, focuses on two-dimensional semiconductors; materials only a few atoms thick that are considered key building blocks for next-generation electronics.
Heat behaving differently than expected
In most materials, heat flows diffusively: it gradually spreads from hotter to colder regions. However, the researchers observed that in ultrathin semiconductors such as molybdenum disulfide (MoS鈧�) and molybdenum diselenide (MoSe鈧�), heat transport follows a more complex mechanism.
The team identified a regime they call hydro-thermoelastic transport, in which heat flow is strongly affected by both collective phonon behavior and mechanical deformation of the material. As a result, heat propagates significantly more slowly than predicted by conventional mechanisms.
鈥淩ather than simply diffusing, heat in these materials behaves in a more collective way, where it is also affected by thermal expansion,鈥� explains last author Klaas-Jan Tielrooij (黑料福利网, ICN2). 鈥淭his challenges the traditional picture of thermal transport.鈥�
Heat that can remain localized
One of the most striking findings is that heat can remain concentrated near its source for longer periods. Based on the theoretical model developed by the colleagues from the UAB, the researchers identified contributions to heat flow that counteract the usual direction, with a flux that points from cold to hot rather than the other way around.
This unusual behaviour arises from the interplay between thermal effects and mechanical responses in the material. This suggests that heat flow can, in principle, be controlled intrinsically, without altering the composition of the material itself.
Towards improved thermal management
Understanding and controlling heat is a major challenge in modern technology, particularly as devices continue to shrink. Excess heat can limit performance and efficiency in electronic and photonic systems.
The newly discovered transport regime provides fundamental insight into heat flow at the nanoscale and could enable new strategies for thermal management and energy conversion. Potential applications include improved cooling of microchips and more efficient thermoelectric devices.