Abstract
We rigorously calculate intrinsic phonon thermal resistance from four-phonon scattering processes
using rst principles Boltzmann transport methods. Fundamental questions concerning the role of
higher order scattering at high temperature and in systems with otherwise weak intrinsic scattering
are answered. Using diamond and silicon as benchmark materials, the predicted thermal conductiv-
ity including intrinsic four-phonon resistance gives signi cantly better agreement with measurements
at high temperatures than previous rst principles calculations. In the predicted ultrahigh thermal
conductivity material, zincblende BAs, four-phonon scattering is strikingly strong when compared
to three-phonon processes, even at room temperature, as the latter have an extremely limited phase
space for scattering. Including four-phonon thermal resistance reduces the predicted thermal con-
ductivity of BAs from 2200 W/m-K to 1400 W/m-K.
