Molecular dynamics simulations of mechanical properties of monolayer MoS2

Based on the benchmark created by the first principle calculations, the effectiveness of different empirical potential functions, including CVFF1, CVFF2, SW and REBO potentials, on describing the mechanical behavior of single layer MoS2 (SLMoS2) are evaluated. The mechanical properties including the elastic modulus E, Poisson's ratio nu, nonlinear elastic modulus D, failure stress and ultimate strain are considered. It is found that under a small deformation, the REBO and CVFF2 potentials can provide an effective description of the elastic behavior of SLMoS2; whereas under a large deformation, the SW potential gives a more accurate stress value and the CVFF2 potential can only predict the right value under biaxial tension. After modifying the cut-off distances in the REBO potential, the failure strain can be reasonably predicted by the REBO potential; whereas the failure stress will be overestimated by about 20-40% for biaxial and uniaxial tension. The present study can provide help on accurately understanding the mechanical behavior of SLMoS2.