Hydronics – An interdisciplinary investigation of charge and heat transportAward, SNI INSight August 2020
The Swiss National Science Foundation recently pledged 2.7 million Swiss francs in funding for the interdisciplinary Sinergia project “Hydronics”. The project is led by Professor Ilaria Zardo of the Department of Physics, and brings together an interdisciplinary team of researchers from the University of Basel, EPFL, Empa and IBM to study charge and heat transport, and explore new ways of controlling electrical and thermal currents.
Differences in thermal propagation
Electronic systems are growing smaller and more powerful all the time. One drawback of this kind of miniaturization is heat build-up in electronic components. Accordingly, for the computer and electronics industry it is increasingly important to understand the phenomenon of charge and heat transport, and find ways to control it.
Heat in electronic components is produced by mechanical oscillations known as phonons. In a three-dimensional solid, these oscillations habitually spread in a diffuse manner. In two-dimensional materials, however, their propagation closely resembles that of currents in liquids under certain conditions. Accordingly, experts refer to this process as hydrodynamic transport, which exhibits properties clearly distinguishing it from diffuse transport. For example, in hydrodynamic transport a thermal impulse propagates through the medium in a manner similar to a shockwave, with no significant damping, whereas diffuse transport involves substantial losses.
In pursuit of selective control
The ability to effectively harness the hydrodynamic transport regime would pave the way for materials in which the propagation of phonons could be selectively controlled. This would make it possible to design materials that emit heat very rapidly, thereby minimizing heat build-up. The same principle could be used to maintain thermal differences for as long as possible in order to exploit them for power generation purposes.
Such an undertaking requires extensive knowledge in the fields of materials science and equipment engineering, along with experience in computer-assisted transport models and the development of experimental protocols. Consequently, some of Switzerland’s leading researchers in these fields have decided to work together to research the field of hydrodynamic heat and charge transport. Over the next four years, the groups led by Professor Michel Calame (Empa), Professor Nicola Marzari (EPFL) and Dr. Bernd Gostmann (IBM) will work alongside Professor Zardo’s team in pursuit of the shared goal of controlling and conducting both electrical and thermal currents with much greater efficiency than presently possible.
Firstly, the researchers plan to develop theoretical models to describe this form of hydrodynamic transport. These models will be used to predict key variables and phenomena that can subsequently be confirmed experimentally. This will involve designing suitable experiments to demonstrate hydrodynamic transport effects in heat and charge transport. Moreover, the researchers expect to be able to predict hydrodynamic transport phenomena in known 2D and 3D materials with a view to optimizing them by structuring the materials. Finally, microscale devices operating on the basis of hydrodynamic transport effects will be created to demonstrate the operating principle.
In line with the requirements for Sinergia projects, the Hydronics project will involve close collaboration between various groups to conduct groundbreaking research. While basic research will play a major role in the early stages of the project, the participating researchers will also work on applied aspects, particularly in the fields of microfabrication and equipment engineering. Sub-projects will involve doctoral and postdoctoral candidates, equipping them with important know-how in preparation for careers in research or industry.