Review on Phonon Transport within Polycrystalline Materials

As one fundamental problem in materials science research, thermal transport across grain boundaries is critical to many energy-related applications. Due to the complexity of grain boundaries, the current understanding on how a grain boundary interacts with heat carriers is still in its infancy. This review summarizes the current progresses of this important topic, with its further extension to general interfaces. One focus is on major modeling and simulation techniques to predict the thermal resistance of a grain boundary. The corresponding thermal measurements of individual grain boundaries and grain-boundary thermal engineering are also discussed. A better understanding of the grain-boundary phonon transport is critical to many energy-related applications, where the concerned thermal transport within a polycrystalline material can be largely suppressed by grain boundaries.