We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios of about 100-200 at lowest and highest measures temperature were achieved when the positioner applied its maximum force o...

Coherent thermal transport, using thermal channels with length smaller than the mean-free path of the thermal carriers, is important for fundamental study of thermal processes and for new device opportunities in thermal management.1–11 In this Brief Report, we consider a coherent thermal channel formed by cascading a series of nonidentical photonic crystals. We show that its thermal conductance...

In a previous paper [4], a simple model was developed (referred to as Modell) to describe the surface temperature evolution of a 1/8" thick aluminum panel with fixed I" diameter flat bottom holes of different depth in response to a short pulse of radiant energy. That model correctly described the temporal behavior of alii" flat bottom holes. To further validate Model I, a new panel was fabricat...

Experimental conductance histograms built from several thousand successive breakings of sodium nanowires 1,2 exhibit peaks up to rather high conductance values (∼ 100× 2e/h). In this paper, we present results from a disordered free-electron model of a metallic nanowire, which was previously successful in describing both conductance histograms and shot noise measurements in gold nanocontacts wit...

Gapped excitation spectra of Andreev states are studied in oneand two-dimensional (1D and 2D) normal systems in superconducting contacts subject to a parallel magnetic field. In the ballistic regime, a specific interplay between magnetic field spin splitting and the effect of a screening supercurrent is found to preserve timereversal symmetry for certain groups of Andreev states remaining gappe...

We have observed experimentally that the thermal conductance of a 2.76-microm-long individual suspended single-wall carbon nanotube (SWCNT) was very close to the calculated ballistic thermal conductance of a 1-nm-diameter SWCNT without showing signatures of phonon-phonon Umklapp scattering for temperatures between 110 and 300 K. Although the observed thermopower of the SWCNT can be attributed t...

We have analyzed the spectral density of fluctuations of the energy flux through a mesoscopic constriction between two equilibrium reservoirs. It is shown that at finite frequencies, the fluctuating energy flux is not related to the thermal conductance of the constriction by the standard fluctuation-dissipation theorem, but contains additional noise. The main physical consequence of this extra ...

The thermal conductance of individual single crystalline silicon nanowires with diameters less than 30 nm has been measured from 20 to 100 K. The observed thermal conductance shows unusual linear temperature dependence at low temperatures, as opposed to the T3 dependence predicted by the conventional phonon transport model. In contrast to previous models, the present study suggests that phonon-...