Mechanical Properties of All MoS2 Monolayer Heterostructures: Crack Propagation and Existing Notch Study

The outstanding thermal, optical, electrical and mechanical properties of molybdenum disolphide (MoS2) heterostructures make them exceptional candidates for an extensive area of applications. Nevertheless, despite considerable technological and academic interest, there is presently a few information regarding the mechanical properties of these novel two-dimensional (2D) materials in the presence of the defects. In this manuscript, we performed extensive molecular dynamics simulations on pre-cracked and pre-notched all-molybdenum disolphide (MoS2) heterostructure systems using ReaxFF force field. Therefore, we study the influence of several central-crack lengths and notch diameters on the mechanical response of 2H phase, 1T phase and composite 2H /1T MoS2 monolayers with different concentrations of 1T phase in 2H phase, under uniaxial tensile loading at room temperature. Our ReaxFF models reveal that larger cracks and notches decrease the strength of all 2D MoS2 single-layer heterostructures. Additionally, for all studied crack and notch sizes, 2H phase of MoS2 films exhibits the largest strength. Maximum tensile stress of composite 2H/1T MoS2 nanosheet with different concentrations are higher than those for the equivalent 1T phase, which implies that the pre-cracked composite structure is remarkably stronger than the equivalent 1T phase. The comparison of the results for cracked and notched all-MoS2 nanosheet heterostructures reveal that the load bearing capacity of the notched samples of monolayer MoS2 are higher than the cracked ones.