Fig. 4: Thermal rectification in the graphite Tesla valve.
From: A graphite thermal Tesla valve driven by hydrodynamic phonon transport
a,b, Thermal diodicity (the ratio of thermal conductivity in the forward, κf, and reverse, κr, directions) as a function of temperature in graphite Tesla valve samples S1–S3 (a) and the silicon Tesla valve (b). The orange region shows the calculated phonon hydrodynamic temperature window of a 4.5-μm-wide graphite channel in our previous work43. The top schematics illustrate different phonon-transport behaviours in graphite within the hydrodynamic regime and in silicon within the diffusive regime. The error bars in the plots are calculated as \(\left({\kappa }_{{\rm{f}}}/{\kappa }_{{\rm{r}}}\right)\sqrt{{\left({\sigma }_{{\rm{f}}}/{\kappa }_{{\rm{f}}}\right)}^{2}+{\left({\sigma }_{{\rm{r}}}/{\kappa }_{{\rm{r}}}\right)}^{2}}\), in which σf and σr are the standard deviations of κf and κr, respectively.
