Radiative heat transfer at the nanoscale

We give a concise introduction into the radiative heat transfer at the nanoscale discussing the contribution of propagating, frustrated and coupled surface modes [1]. Especially, the latter contribution results in a heat flux, which can exceed the heat flux between two black bodies by several orders of magnitude for distances in the nanometer regime [1]. The prediction of such an enormous heat flux enhancement is usually based on Rytov's fluctuational electrodynamics [2] and has been verified in some very recent experiments [3,4,5]. Our aim is to show how the theoretical expression describing the nanoscale heat flux can be interpreted in terms of transmission coefficients and the universal quantum of thermal conductance by means of concepts of mesoscopic physics [6]. Such a formulation allows for studying the fundamental limits of radiative heat transfer [7,8] emphasizing the trade-off between the number of contributing modes and their transmission coefficient. [1] K. Joulain, J.-P. Mulet, F. Marquier, R. Carminati, and J.-J. Greffet, Surface Science Reports 57, 59 (2005). [2] S. M. Rytov, Y. A. Kravtsov, and V. I. Tatarskii, Principles of Statistical Radiophyics (Springer, New York), Vol. 3. (1989). [3] S. Shen, A. Narayanaswamy, and G. Chen, Nano Lett. 9, 2909 (2009). [4] E. Rousseau, A. Siria, G. Jourdan, S. Volz, F. Comin, J. Chevrier, and J.-J. Greffet, Nature Photonics 3, 514 (2009). [5] R. Ottens, V. Quetschke, S. Wise, A. Alemi, R. Lundock, G. Mueller, D. H. Reitze, D. B. Tanner, B. F. Whiting, Phys. Rev. Lett. 107, 014301 (2011). [6] S.-A. Biehs, E. Rousseau, and J.-J. Greffet, Phys. Rev. Lett. 105, 234301 (2010). [7] P. Ben-Abdallah and K. Joulain, Phys. Rev. B 82, 121419 (R) (2010). [8] S. Basu and Z. M. Zhang, J. Appl. Phys. 105, 093535 (2009).