Ring-crack initiation in micrometer-scale Hertz indentation simulated by controlled molecular dynamics

Hertz indentation has been simulated using the controlled molecular dynamics proposed by the authors. The result of the simulation shows that a defect, which may develop into a ring crack, can be initiated during indentation even in monocrystalline silicon with no preexisting defect. The defect initiation occurs just outside the outer periphery of the contact surface between silicon and a diamond indenter when the static tensile stress is coupled there with the dynamic force associated with acoustic waves that may come from nearby amorphous areas in the field.