Physical processes describing heat transfer at short lengthscale

Karl Joulain (1)

1 LET - Laboratoire d'études thermiques

We explore in this article physical processes describing heat transfer at short time and length scales. First, we show that the physical phenomena describing classical heat transfer are no longer valid when the dimension involved goes below some characteristic lengths like the heat carrier mean free path or wavelength. In particular, we present heat transfer calculations in the ballistic regime when heat carriers fly from one border of the considered system to the other. Heat conduction which values in nature span only a range of 4 orders of magnitude will particularly focus our attention. We will show how the new development of nanotechnology paves the way to the conception of new very low thermal conductivity materials with outstandingly interesting properties. Finally, we will review thermal radiation properties in the near-field i.e. at subwavelength distances. We will see that at such distances, thermal radiation coherence properties drastically change and open the way to the conception of new thermal sources.

Domaines: Micro et nanotechnologies/Microélectronique

Karl Joulain. Physical processes describing heat transfer at short lengthscale. 2008. ⟨hal-00267820⟩