Eur. Phys. J. E (2010) 33: 1-9
https://doi.org/10.1140/epje/i2010-10644-9

Regular Article

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

^* e-mail: fqpotiguar@ufpa.br

Received: 29 April 2010
Accepted: 20 July 2010
Published online: 17 September 2010

Abstract

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.