Using confocal-microscopy we investigate the structure of binary mixtures of colloidal hard spheres with size ratio q=0.61. As a function of the packing fraction of the two particle species, we observe a marked change of the dominant wavelength in the pair correlation function. This behavior is in excellent agreement with a recently predicted structural crossover in such mixtures. In addition, the repercussions of structural crossover on the real-space structure of a binary fluid are analyzed. We suggest a relation between crossover and the lateral extension of networks containing only equally sized particles that are connected by nearest neighbor bonds. This is supported by Monte-Carlo simulations which are performed at different packing fractions and size ratios.
@article{arxiv.0704.0343,
title = {Experimental observation of structural crossover in binary mixtures of colloidal hard spheres},
author = {Jörg Baumgartl and Roel P. A. Dullens and Marjolein Dijkstra and Roland Roth and Clemens Bechinger},
journal= {arXiv preprint arXiv:0704.0343},
year = {2007}
}