Size effects on heat transport in small systems: Dynamical phase transition from diffusive to ballistic regime

Abstract

The size effects on heat conduction in small systems are analyzed by using irreversible thermodynamics and Boltzmann equation derived heat transport models. The system's size dependent group velocity of heat waves and thermal response of the system are studied in the diffusive-ballistic transition of heat transport. A critical range of values for the Knudsen number is found which features a dynamic phase transition between the diffusive and ballistic regimes. The transition system's sizes range from 10 to 380 μm. © 2009 American Institute of Physics.