Heat Superdiffusion in Plasmonic Nanostructure Networks

Abstract

The heat transport mediated by near-field interactions in networks of plasmonic nanostructures is shown to be analogous to a generalized random walk process. The existence of superdiffusive regimes is demonstrated both in linear ordered chains and in three-dimensional random networks by analyzing the asymptotic behavior of the corresponding probability distribution function. We show that the spread of heat in these networks is described by a type of Lévy flight. The presence of such anomalous heat-transport regimes in plasmonic networks opens the way to the design of a new generation of composite materials able to transport heat faster than the normal diffusion process in solids.

Anomalous law of cooling

“…Also, the heat transport mechanism at the nanoscale, which allows on to go beyond the normal diffusion in solids 59 . In addition, diffusion poses challenges in the understanding of fundamental concepts in statistical physics, such as the validation of the FDT 22 , general properties of the correlation function 5 , entropy 23 , ergodicity 24,25,48,60 , and Khinchin theorem 24,48 .…”

Ballistic near-field heat transport in dense many-body systems

“…In particular, we prove the existence of a nonmonotonic transition between a superdiffusive regime, previously observed in Ref. [31], and a ballistic regime that appears in denser media and that also leads to dramatically faster relaxation dynamics. We also show that this transition is associated with a change in the polarization of the dominant modes in the transport.…”

“…Furthermore, heat transport within a collection of nanoparticles has been studied in Ref. [31], and the existence of a superdiffusive regime has been found, albeit within a dipolar approximation.In the present Letter, we employ a recently developed, exact theoretical framework [32] to investigate near-field radiative heat transport in N -body systems consisting of parallel planar slabs separated by vacuum, in which radiation is the only source of thermal relaxation. We show that the temperature dynamics and steady-state profile of the system depend strongly on geometric parameters such as the system density, which imply different heat-transport regimes.…”

“…Furthermore, heat transport within a collection of nanoparticles has been studied in Ref. [31], and the existence of a superdiffusive regime has been found, albeit within a dipolar approximation.…”

“…[31], to understand and classify the various transport regimes in this kind of system, it is useful to study the power exchanged between layers in the limit of large N . For convenience, we make the simplifying assumption that the temperature differences involved in the system are small enough to allow a linearization of n ,j .…”