Numerical scheme analysis towards prediction of nanoscale fracture toughness of silicon at room temperature

In this paper, a numerical scheme towards prediction of the fracture toughness has been proposed based on molecular dynamics. Causes of deviations of predicted values have been analyzed, which are mainly due to the calculation system size, the initial crack and the boundary condition. With the improved scheme, a stable value of the fracture toughness independent on crack length is obtained. Besides, under extremely high stresses, it is found that emission of shuffle-set dislocations is responsible for ductile fracture of silicon at 300 K. Furthermore, the reconstruction of the tips is found strengthening silicon to block cracking, which increases the fracture toughness.