Radiative resistance at the nanoscale: Thermal barrier

In the present article the radiative thermal current and radiative resistance are introduced and investigated in a system of parallel slabs. The system is placed in an environment with a constant temperature and subjected to a constant temperature gradient, which causes a radiative energy flux through the system. We have calculated the steady-state temperature profile of the system, assuming that the material and thickness of the middle slab could be different from the other slabs. We propose the exact formulation for calculating the thermal current and thermal resistances in both linear and nonlinear regimes. According to our results, the middle slab acts as a thermal barrier, and depending on the width of this barrier, an extreme thermal isolation is achievable. Simulation results indicate that the thermal resistance of the barrier is an increasing function of the thickness for near-field separation distances but is virtually insensitive to the barrier width in the far-field regime. The long-range character of the radiative heat transfer which occurs in systems with identical slabs is also discussed.