From crystal to amorphous: A novel route to unjamming in soft disk packings
Departamento de Fısica, ICEN, Universidade Federal do Pará, Av. Augusto Correa, 1, 66075-110, Pará, Brazil
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Accepted: 20 July 2010
Published online: 17 September 2010
Numerical studies on the unjamming packing fraction of bi- and polydisperse disk packings, which are generated through compression of a monodisperse crystal, are presented. In bidisperse systems, a fraction f + = 0.400 up to 0.800 of the total number of particles has their radii increased by R , while the rest has their radii decreased by the same amount. Polydisperse packings are prepared by changing all particle radii according to a uniform distribution in the range [- R, R] . The results indicate that the critical packing fraction is never larger than the value for the initial monodisperse crystal, = / , and that the lowest value achieved is approximately the one for random close packing. These results are seen as a consequence of the interplay between the increase in small-small particle contacts and the local crystalline order provided by the large-large particle contacts.
© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2010