Crystallization of hard-sphere glasses.
We study by molecular dynamics the interplay between arrest and crystallization in hard spheres. For state points in the plane of volume fraction (0.54 <or= varphi <or= 0.63) and polydispersity (0 <or= s <or= 0.085), we delineate states that spontaneously crystallize from those that do not. For noncrystallizing (or precrystallization) samples we find isodiffusivity lines consistent with an ideal glass transition at varphi_{g} approximately 0.585, independent of s. Despite this, for s < 0.05, crystallization occurs at varphi > varphi_{g}. This happens on time scales for which the system is aging, and a diffusive regime in the mean square displacement is not reached; by those criteria, the system is a glass. Hence, contrary to a widespread assumption in the colloid literature, the occurrence of spontaneous crystallization within a bulk amorphous state does not prove that this state was an ergodic fluid rather than a glass.
Zaccarelli
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E
Dipartimento di Fisica and CNR-INFM-SOFT, Universitá di Roma La Sapienza, 00185, Roma, Italy.
Valeriani
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C
Sanz
E
E
Poon
W C K
WC
Cates
M E
ME
Pusey
P N
PN