Exploring the Extremes of Heat Conduction in Anisotropic Materials

Anisotropic solids possess thermal conductivities ranging from among the highest found in nature, as in the in-plane thermal conductivity of graphite, to the lowest, as in the cross-plane thermal conductivity of disordered layered crystals. Though these extremes of thermal conductivity make anisotropic materials attractive for diverse applications such as thermal management and thermal insulation, the microscopic physics of heat conduction in these materials remain poorly understood. In this review article, we discuss the recent advances in our understanding of thermal phonon transport in anisotropic solids obtained using new theoretical, computational, and experimental tools.