Temperature Profile for Ballistic and Diffusive Phonon Transport in a Suspended Membrane with a Radially Symmetric Heat Source

J. T. Karvonen ； T. Kühn ； I. J. Maasilta

《Chinese Journal of Physics》 49卷1期 (2011/02) Pp. 435-442

並列摘要

Temperature profiles for phonon heat transport in a suspended membrane with a radially symmetric heat source are calculated for two extreme cases: (1) purely ballistic transport and (2) purely diffusive transport. Theoretical results confirm that it is possible to distinguish between these two transport mechanisms on the basis of the radial temperature profiles alone. Model results are also compared with the experimental data measured using 40-nm-thick free-standing silicon nitride membranes at temperatures below 1 K; superconductor-normal metal-superconductor tunnel junction (SINIS) thermometers are used for the measurements. The measured temperature profile is in quantitative agreement with the results obtained using the ballistic model only when the distance is below 50 μm.