Silicene,a monolayer of silicon atoms arranged in honeycomb lattice,has been viewed as a new type of atomic-layered material with outstanding properties,just like graphene.Its potential applications in nanoelectronics and solar energy conversion lead it to receive exceptional attention from a wide community of scientists and engineers.However,to the best of our knowledge,the thermal conductivity of single-layer silicene has only been predicted from molecular dynamics simulations with original Tersoff potential,which is not very accurate because the original Tersoff potential cannot reproduce the buckling structure of silicene.In order to accurately predict the thermal conductivity of silicene,we optimized the Stillinger-Weber potential parameters to reproduce the low buckling structure of silicene and the full phonon dispersion curve obtained from ab initio calculations.With this optimized SW potential,the equilibrium and nonequilibrium molecular dynamics simulations,and anharmonic lattice dynamics(ALD)calculations are performed.In order to get more accurate prediction,anharmonic lattice dynamics(ALD)approach is used with interatomic force constants(IFCs)calculated from first-principles calculations.All the four methods above consistently result in very low thermal conductivity which is much smaller than that of bulk silicon.Unlike graphene,the out-of-plane vibrational modes contribute less than 10 percent of the total thermal conductivity.The difference is explained by the presence of small buckling,which breaks the reflectional symmetry of the structure.The flexural modes are thus not purely out-of-plane vibration and have strong scattering with other modes.