Prediction of mechanical properties for defective monolayer MoS2 with single molybdenum vacancy defects using molecular dynamics simulations

It is revealed by recent experimental and theoretical nanoindentation studies that the low concentration of monovacancy produces an abnormal noticeable stiffening effect on graphene sheets, which depending on the defect type. As for graphene-like quasi-two dimensional (2D) nanomaterials, the single-layer molybdenum disulfide (SLMoS2) has intrinsic structural defects that are distinct to graphene. Therefore, it is intriguing to investigate if any kind of defects will lead to such unique effect on the mechanical properties of SLMoS2, including the elasticity and strength. Following our preliminary studies on the VMoS3 point defect, herein, we perform molecular dynamics simulations to look into the effect of the low concentration of single molybdenum vacancy defects on the mechanical properties of SLMoS2, under uniaxial tensile tests. The defect fractions of the single Mo vacancy varying from 0.1% to 1.0% are considered in our works, together with the random and regular vacancy distributions. Single molybdenum vacancy defects are found, as common intuition would suggest, to reduce the mechanical properties of SLMoS2, including the elastic modulus and tensile strength. The effect of chirality on the mechanical properties of the SLMoS2 is also discussed in the present work.