Colloquium: Phononic thermal properties of two-dimensional materials

The thermal conductivity of 3D samples is usually intensive. However, this holds only when phonon transport is diffusive and the sample is sufficiently large. In this review, a framework is presented that shows how phonon scattering in 2D materials influences thermal transport properties that depend on geometry, substrate and interlayer coupling, and imperfections. These considerations suggest ways of enabling new thermoelectric materials, thermal conductors or insulators, and perhaps even phononic computing devices.