Four-phonon and normal scattering in 2D hexagonal structures

Comprehensive understanding of phonon transport will facilitate the exploration of materials. Four-phonon scattering is find to be important to determine thermal conductivity in many materials, and normal scattering (N process) could lead to some unique phonon transport behaviors, especially in 2D materials . In this work, we studied four-phonon and normal scattering in hexagonal structures, both of which were found to be significant. With the increase of atomic mass ratio, the relative four-phonon scattering is gradually enhanced, whereas N process is weakened. Callaway model and Allen’s modified models were used to approximate the thermal conductivity , and we find that the models are applicable in some cases with relative weak N scattering intensity.