Near Field Heat Transfer between Random Composite Materials: Applications and Limitations

Abstract

Abstract:We present a theoretical study of the limits and bounds of using effective medium approximations in the calculation of the near field radiative heat transfer between a composite system made of Au nanoparticles in a SiC host and an homogeneous SiC slab. The effective dielectric function of the composite slab is calculated using three different approximations: Maxwell-Garnett, Bruggeman, and Looyenga's. In addition, we considered an empirical fit to the effective dielectric function by Grundquist and Hunderi. We show that the calculated value of the heat flux in the near field is dependent on the model, and the difference in the effective dielectric function is larger around the plasmonic response of the Au nanoparticles. This, in turn, accounts for the difference in the near field radiative heat flux. For all values of filling fractions, the Looyenga approximation gives a lower bound for the heat flux.

Enhancement of near-field thermal radiation between composite materials with gradient plasmonic nanoparticles

“…27 It is important to note, however, that employing composite materials typically yields a reduced heat flux compared to bulk materials, impeding effective heat flux control. [24][25][26][27][28][29] By combining gradient materials with CMs, and considering the excellent performance of CMs composed of gradient nanoparticles in optical regulation, [30][31][32] we believe that the implementation of this composite has the potential to enhance the heat flux while preserving its adjustability.…”

Resonant enhancement of the near-field radiative heat transfer in nanoparticles

“…Modification of the dielectric response can be achieved in several ways. In composite materials, the dielectric function can be modified by a suitable combination of host and inclusions 12,13 . The simplest configuration of a composite is a layered media that can give rise to the different surface and hyperbolic modes [14][15][16][17][18] , which allow the enhancement of the radiative heat transfer at subwavelength scales 19,20 .…”

Near-Field Radiative Heat Transfer around the Percolation Threshold in Al Oxide Layers

“…44 Other alternatives to modify the NFRHT include the use of phase change materials 45,46 and composite systems, which constitute a way to tune the heat transfer at the nanoscale. 47,48 In these references, the dispersion relation of surface modes is modified by spoof plasmons or by the hybridization of plasmon and phonon polariton modes. 49−51 Among the many materials that are used in nanodevices, aluminum (Al) has gained a lot of interest, 52,53 in particular, in plasmonics, since the wavelength region of light that can be accessed extends to the ultraviolet (UV).…”

“…Dynamic modulation of heat transfer is also possible by applying an external mechanical pressure in microdevices . Other alternatives to modify the NFRHT include the use of phase change materials , and composite systems, which constitute a way to tune the heat transfer at the nanoscale. , In these references, the dispersion relation of surface modes is modified by spoof plasmons or by the hybridization of plasmon and phonon polariton modes. − …”