Penetration force-penetration depth curve during the penetration with a probe radius of 8 nm. The two penetration depths D1 of 0.65 nm and D2 of 0.82 nm have the same penetration force. The two insets show instantaneous defect structures at D1 and D2, in which atoms are colored according to their BAD values and FCC atoms are not shown.
Li et al. Nanoscale Research Letters 2013 8:514 doi:10.1186/1556-276X-8-514