Phonon transport beyond Rayleigh scattering in spatially correlated disorder

The performance and reliability of numerous technologies, from electronics and thermoelectrics to nuclear reactors, are constrained by the thermal conductivity of solid-state components. In many cases, these materials include substantial amounts of defects and nanostructures. Thus, understanding how disorder impacts phonon scattering and heat transport is a critical research challenge. It is known that the scattering rates of phonons due to point defects decrease as the fourth power of the mode frequency (Rayleigh scattering). Here, we demonstrate that this power law can be modified by introducing spatial correlations in the defect distribution, resulting in a substantial suppression of the thermal conductivity. To illustrate this, we apply a Chebyshev polynomial Green's function method to simple mass-disordered models for an exact treatment of disorder in large supercells (tens of millions of atoms).