title: Threshold crack speed controls dynamical fracture of silicon single crystals.
abstract: Fracture experiments of single silicon crystals reveal that after the critical fracture load is reached, the crack speed jumps from zero to approximately 2 km/sec, indicating that crack motion at lower speeds is forbidden. This contradicts classical continuum fracture theories predicting a continuously increasing crack speed with increasing load. Here we show that this threshold crack speed may be due to a localized phase transformation of the silicon lattice from 6-membered rings to a 5-7 double ring at the crack tip.
authors.affiliation: Laboratory for Atomistic and Molecular Mechanics, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room 1-272, Cambridge, MA 02139, USA. mbuehler@MIT.EDU
authors.forename: Markus J
authors.initials: MJ
authors.lastname: Buehler
authors.forename: Harvey
authors.initials: H
authors.lastname: Tang
authors.forename: Adri C T
authors.initials: AC
authors.lastname: van Duin
authors.forename: William A
authors.initials: WA
authors.lastname: Goddard