Despite extensive previous research, the suppression in phonon conduction at the nanoscale still calls into questions on the interaction of phonons with various sources of boundary scatterings. In this work, a combination of Boltzmann transport model and the experiments finds that the bridges contribute to phonon mean free paths proportional to its volume fraction despite its negligible contribution to net heat flux. A statistical analysis of boundary scattering reveals that transport characteristics of phonon evolves from Brownian motion to Lévy walk due to phonons trapped within the bridges.
- Yongjoon Kim
- Takashi Kodama
- Woosung Park
