Momentum and spectral bandgaps: shaping the near-field radiative heat transfer between plasmonic hypercrystals

This study theoretically investigates the near-field radiative heat transfer (NFRHT) between two plasmonic hypercrystals (PlHs). Each PlH is formed by a periodic variation in the dielectric response of a hyperbolic metamaterial (HMM), achieved by incorporating plasmonic films. We analyzed the contribution of the high-k modes of the PlHs to NFRHT, which result in spectral and momentum bandgaps forming in the system's energy transmission coefficient. We found that the heat flux between the PlHs increases up to 480% compared to two homogeneous slabs made of the same HMM due to the inclusion of thin plasmonic layers. We also explored the control of heat transfer by tuning the system's geometrical parameters and the effects of the stacking order of the different phases on the NFRHT.