Phonon transport in antisite-substituted hexagonal boron nitride nanosheets: A molecular dynamics study
Man Zhou, Ting Liang, Bingyang Wu, Jiaju Liu, Ping Zhang
Abstract
This study uses non-equilibrium molecular dynamics simulations to investigate the impact of antisite substitution on thermal conductivity. The phonon-dispersion curve and predicted thermal conductivity of pristine hexagonal boron nitride nanosheets (hBNNSs) show good agreement with the experiment results, indicating the reliability of the extep potential. It is clear that both neighboring substitution (NS) and random substitution (RS) drastically reduce the thermal conductivity of hBNNSs, of which RS has a larger effect. Calculations for the participation ratio and relaxation time show that the localization is the primary cause for the reduction in thermal conductivity when the defect concentration is low. When the defect concentration is higher, the primary cause is phonon-defect scattering in all phonon modes. RS has a larger effect on the phonon modes with long mean free paths, while NS has a larger effect on phonon modes with various lengths of mean free paths.