Steady-state temperature distribution under near-field radiative heat transfer inside a linear chain of polaritonic nanoparticles

Highlights: • Nonequilibrium steady-state temperature distribution inside a linear chain of polaritonic nanoparticles is investigated. • The existence of the linear temperature profile and anomalous temperature variations in the inner region and near the boundary of a dense chain in vacuum, respectively. • Effects of the chain density, dielectric materials and the presence of a homogeneous nonabsorbing background medium are examined. • Tailoring the equilibrium temperature of the thermal drive chain by manipulating its neighboring chains. Thermal transport mediated by near-field interactions is superdiffusive in an ordered network of nanoparticles, such as linear chains. Based on such nanostructures, here we study a classical thermal-nonequilibrium problem, that is, the steady-state temperature distribution inside the chain of equally spaced polaritonic nanoparticles. The existence of the linear temperature profile and anomalous temperature variations in the inner region and near the boundary of a dense chain embedded in vacuum, respectively, is demonstrated by analyzing the effective radiative thermal conductivity within the system. Such temperature distributions are closely relevant to the strength of propagating surface modes sensitive to the chain density and dielectric material. We also demonstrate that, the presence of a homogeneous nonabsorbing background medium renders the steady-state temperature profile of the dense chain nonlinear, as well as enhancing drastically the long-distance heat exchange by two orders of magnitude relative to the vacuum case. This enhancement is a result of the high density of propagating waves in the medium, and is further confirmed by analyzing the energy density distribution over the chain. Furthermore, in a complex system consisting of many parallel chains, we show that, in steady state, temperatures of the thermal drive chain are allowed to tailor by its neighboring chains due to many-body interactions. This work opens ways to qualitatively assess and manipulate the stationary temperature field in advanced nanostructures, such as topological plasmonic chains and nanoparticle arrays.