title: Pressure-induced structural transformation in radiation-amorphized zircon.
abstract: We study the response of a radiation-amorphized material to high pressure. We have used zircon ZrSiO4 amorphized by natural radiation over geologic times, and have measured its volume under high pressure, using the precise strain-gauge technique. On pressure increase, we observe apparent softening of the material, starting from 4 GPa. Using molecular dynamics simulation, we associate this softening with the amorphous-amorphous transformation accompanied by the increase of local coordination numbers. We observe permanent densification of the quenched sample and a nontrivial "pressure window" at high temperature. These features point to a new class of amorphous materials that show a response to pressure which is distinctly different from that of crystals.
authors.affiliation: Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, United Kingdom.
authors.forename: Kostya
authors.initials: K
authors.lastname: Trachenko
authors.forename: V V
authors.initials: VV
authors.lastname: Brazhkin
authors.forename: O B
authors.initials: OB
authors.lastname: Tsiok
authors.forename: Martin T
authors.initials: MT
authors.lastname: Dove
authors.forename: E K H
authors.initials: EK
authors.lastname: Salje