Remarkable suppression of thermal conductivity by point defects in MoS2 nanoribbons

By molecular dynamics simulation, we demonstrate that both sulfur vacancies (VS) and oxygen substitutions to sulfur (SO) can significantly reduce thermal conductivity of monolayer MoS2 nanoribbons, but the suppression of thermal conductivity by vacancies is stronger than that by substitutions. We perform the vibrational eigenmodes analysis and find that the strong localization of phonons of all modes by defects results in the severe reduction of thermal conductivity of MoS2 nanoribbons. Further spectra analysis reveals that the localized modes are located in the sites of defects and the sites around defects, due to change of force constant at these sites.