A study with the participation of the Institute of Optics provides new knowledge about the way in which sets of nanoparticles exchange heat by radiation with each other and with their environment. Until now, scientists knew that radiative heat exchange - every hot object emits light, allowing it to release heat - can be much more efficient at the nanoscale than at the macroscale. However, the methods for calculating nanoparticle thermalization dynamics required complex computational resources.
The new theoretical framework developed allows an efficient and simple description even with thousands of nanoparticles. The work is published in the journal Physical Review Letters.

Controlling radiative heat transfer at the nanoscale could be applied in photovoltaic solar energy, to convert heat from motors and factories into usable electricity, or in the cooling of electronic components in microchips, in order to avoid overheating of computers and to facilitate the development of chips with more transistors. “Our theoretical framework breaks down the dynamics of radiation heat transfer using simple mathematical techniques. In this way, we have not only been able to study the thermalization of large and complicated systems, but we have also found new physical behaviors that challenge our intuition ”, says our colleague Alejandro Manjavacas and director of the work.

Scientists have found that when an array of nanoparticles has a certain amount of heat initially stored, the system will approximate the temperature of its surroundings in the same way. And that will happen regardless of which particles are hot. In contrast, if the total heat initially in a system is zero, such as when one nanoparticle is hotter than the environment and another is cooler, the system reaches thermal equilibrium more quickly.

“Another interesting behavior consists of an oscillating evolution of the temperature of a nanoparticle as it thermalizes with the environment. In the course of thermalization, the nanoparticle is cooled and reheated several times, although the environment always remains at the same temperature ”, add Diego Dalvit and Wilton Kort-Kamp, scientists at the Los Alamos National Laboratory (USA). .).

The IO-CSIC, the Los Alamos National Laboratory and the University of New Mexico (USA) participate in the work.

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