Enhancing near-field radiative heat transfer by means of superconducting thin films

We present a theoretical study of the near-field radiative heat transfer between high-Tc superconducting thin films. We focus on ceramic materials like optimally doped YBa2Cu3O7−δ, with a critical temperature Tc=93 K. We show that thin films significantly enhance the radiative heat transfer by efficiently coupling each interface’s optical modes. The heat transfer between thin films turns out to be up to one order of magnitude higher than that for bulk plates both in the normal and superconducting states. On the other hand, the drastic change of the optical response above and below Tc also plays an important role, since the superconducting phase transition leads to an abrupt suppression of the total heat flux. Our findings are relevant for the rational design of proficient thermal devices involving thin layers of this kind of materials. The strong temperature-dependent modulation of the heat flux across the phase transition is promising for thermal switches and thermal emitters’ control.