2017/05/31 by Frank Rietz, Charles Radin, Harry L. Swinney +1 · 1 citation
Physics and Astronomy · #cond-mat.soft #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevlett.120.055701
published as Phys. Rev. Lett. 120, 055701 (2018)
arxiv created 2017/12/14 · arxiv updated 2018/02/07
We present an experiment on crystallization of packings of macroscopic granular spheres. This system is often considered to be a model for thermally driven atomic or colloidal systems. Cyclically shearing a packing of frictional spheres, we observe a first order phase transition from a disordered to an ordered state. The ordered state consists of crystallites of mixed FCC and HCP symmetry that coexist with the amorphous bulk. The transition, initiated by homogeneous nucleation, overcomes a barrier at 64.5% volume fraction. Nucleation consists predominantly of the dissolving of small nuclei and the growth of nuclei that have reached a critical size of about ten spheres.