13:45 〜 14:00
▲ [6p-C22-1] [JSAP Young Scientist Award Speech] Heat guiding, focusing and rectification using phononic nanostructures
キーワード：Phononic crystal, thermal conductivity, heat transport
We experimentally and theoretically demonstrate directional ballistic heat transport in phononic nanostructures and use this phenomenon for heat guiding and focusing.
First, using micro-TDTR experiments and Monte-Carlo simulations, we studied heat transport in silicon thin films with aligned and staggered periodic arrays of holes, and demonstrated that significant difference in thermal conductivity appears when the characteristic size of the structures becomes smaller than 100 nm. This difference is attributed to ballistic phonon transport in the structures with the aligned lattice.
Next, we demonstrated that these structures can act as a media that guides and as a source that emits ballistic phonons in solids. This emission was coupled into nanowires, where the ballistic path of the phonons was continued, and corresponding nanowire length and temperature dependencies were observed.
Finally, we used this concept to create thermal lens nanostructures which can focus thermal energy in the focal point. We demonstrate that this thermal lens creates a 100-nm-wide hot spot and can be used as a thermal diode. These results motivate the concept of ray-like heat manipulations at the nanoscale.
First, using micro-TDTR experiments and Monte-Carlo simulations, we studied heat transport in silicon thin films with aligned and staggered periodic arrays of holes, and demonstrated that significant difference in thermal conductivity appears when the characteristic size of the structures becomes smaller than 100 nm. This difference is attributed to ballistic phonon transport in the structures with the aligned lattice.
Next, we demonstrated that these structures can act as a media that guides and as a source that emits ballistic phonons in solids. This emission was coupled into nanowires, where the ballistic path of the phonons was continued, and corresponding nanowire length and temperature dependencies were observed.
Finally, we used this concept to create thermal lens nanostructures which can focus thermal energy in the focal point. We demonstrate that this thermal lens creates a 100-nm-wide hot spot and can be used as a thermal diode. These results motivate the concept of ray-like heat manipulations at the nanoscale.