Stretching and breaking of monolayer MoS2-an atomistic simulation

We report on the simulation of the nanoindentation process of monolayer MoS2 using molecular-dynamics simulations and a density-functional based tightbinding method. A circular sheet of MoS2 with clamped boundaries was indented by a slowly moved tip, which deformed and finally pierced the layer. We found the Young's modulus of monolayer MoS2 to be 262 GPa, which is in good agreement with experimental observations. Furthermore, the energetic and structural behavior during the indentation process was analyzed. Elasticity theory supplies the necessary equations to explain the experiment. Thereby, the nature of the linear term in the force-deflection relation is discussed.