Mechanical Properties of Monolayer Molybdenum Disulfide

We use atomistic simulations to study mechanical properties of monolayer molybdenum disulfide MoS₂. Using molecular dynamic (MD) simulations, we investigate the nano-fracture properties of monolayer MoS₂ under mixed mode I and II loadings. The MD simulations are used to obtain the critical stress intensity factors of both armchair and zigzag cracks as a function of applied loading phase angle. Our atomistic simulations predict that armchair cracks are tougher than zigzag cracks, and both armchair and zigzag cracks tend to propagate along a zigzag path. Furthermore, we use density functional theory (DFT) to investigate how point defects influence the mechanical properties of nanoribbons. Our DFT simulations show that missing one S atom does not significantly affect the mechanical strength of monolayer MoS₂, whereas missing one Mo atom can reduce the maximum strength of single layer MoS₂ sheet by about 10%.