Experimental observation of structural crossover in binary mixtures of colloidal hard spheres.
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.
Baumgartl
Jörg
J
2. Physikalisches Institut, Universität Stuttgart, 70550 Stuttgart, Germany. j.baumgartl@physik.uni-stuttgart.de
Dullens
Roel P A
RP
Dijkstra
Marjolein
M
Roth
Roland
R
Bechinger
Clemens
C