Grants and Contributions:

Grant or Award spanning more than one fiscal year. (2017-2018 to 2022-2023)

Until the 2000s only near-field heat exchanges between two objects had been theoretically and experimentally investigated and the mechanisms for energy transport in systems composed of a collection of different objects in mutual interaction was still unexplored and even out of range of the fluctuational electrodynamic theory introduced by Polder and van Hove in the beginning of 70s describing two-body heat exchanges. In 2011, we have introduced the first theoretical framework to deal with near-field heat exchanges in many-body systems in the approximation of small objects. This result consists in a generalization of the coupled dipole theory initially introduced in optics for fluctuating dipoles. In particular, a Meir-Wingreen-Landauer-type formula for the radiative heat transport in interacting N-body systems has been derived. A generalization of this theory to macroscopic objects has revealed the existence of purely many-body effects such as thermal photon tunneling enhancement which allows us to extend the near-field effects to larger separation distances using a passive relay system intercalated between two bodies in near-field interaction. All these pioneer works have opened the way to study the physics of heat exchanges in more or less complex plasmonic networks in regimes where near-field interactions are dominating the energy transport. But, to date this physics remains largely unexplored.

The first goal of the present research program is to derive the main laws which govern those exchanges from the dilute regime of interaction to the dense regime where non-local effects must be taken into account. The dynamics of N-body systems (i.e. the thermal relaxation), the existence of multiple equilibrium states (i.e. multistability) as well as the heat transport regimes versus the density and the structural order of networks will be investigated both in the framework of a mean field theory and by means of a Landauer formalism.

The second goal of this research program will consist in investigating the tunability of heat transfers in N-body systems by considering magneto-optical networks under the action of an external magnetic field. We will specifically study thermomagnetic effects such as thermal Hall transport and thermal magnetoresistance in four-terminal and 2D N-body systems.

In parallel to these theoretical developments an experimental platform based on the thermo-dependence of the electrical resistance of nanobeams will be developed in order to measure raduatuve heat-exchanges at nanoscale in N-body systems and to investigate these exchanges through complex nanowire networks.