Effects of a grain boundary loop on the thermal conductivity of graphene: A molecular dynamics study

Thermal transport in graphene with one type of grain boundary loop was investigated using non-equilibrium molecular dynamics simulation method. The results showed that thermal conductivity is very sensitive to defect concentration. It rapidly decreases in the presence of a defect. This is attributed the phonon defects scattering which shorten the phonon mean free paths leading to the reduction in thermal conductivity. Furthermore, temperature dependency of thermal conductivity of pristine and defected graphene was determined. The results indicated that thermal conductivity of defect-free graphene varies significantly with temperature, while thermal conductivity of graphene with defect remains nearly invariant with the temperature of the system. This implies the possibility of phonon-defect scattering domination over Umklapp phonon-phonon scattering in graphene with defect.