title: Nanosecond homogeneous nucleation and crystal growth in shock-compressed SiO2.
abstract: Understanding the kinetics of shock-compressed SiO2 is of great importance for mitigating optical damage for high-intensity lasers and for understanding meteoroid impacts. Experimental work has placed some thermodynamic bounds on the formation of high-pressure phases of this material, but the formation kinetics and underlying microscopic mechanisms are yet to be elucidated. Here, by employing multiscale molecular dynamics studies of shock-compressed fused silica and quartz, we find that silica transforms into a poor glass former that subsequently exhibits ultrafast crystallization within a few nanoseconds. We also find that, as a result of the formation of such an intermediate disordered phase, the transition between silica polymorphs obeys a homogeneous reconstructive nucleation and grain growth model. Moreover, we construct a quantitative model of nucleation and grain growth, and compare its predictions with stishovite grain sizes observed in laser-induced damage and meteoroid impact events.
authors.affiliation: Department of Physics, Stanford University, 496 Lomita Mall, Stanford, California 93405, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Department of Electrical Engineering, Stanford University, 496 Lomita Mall, Stanford, California 93405, USA.
authors.forename: Shai B
authors.initials: SB
authors.lastname: Jester
authors.affiliation: Department of Materials Science and Engineering, Stanford University, 496 Lomita Mall, Stanford, California 93405, USA.
authors.forename: Tingting
authors.initials: T
authors.lastname: Qi
authors.affiliation: Department of Materials Science and Engineering, Stanford University, 496 Lomita Mall, Stanford, California 93405, USA.
authors.forename: Evan J
authors.initials: EJ
authors.lastname: Reed