DOI: 10.1209/epl/i2003-00193-6
Europhys. Lett., 61 (3) , pp. 415-421 (2003)

Dynamical instability in driven colloids

J. Chakrabarti¹, J. Dzubiella² and H. Löwen<sup>2

1</sup>  S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III Salt Lake, Calcutta, 700091, India
²  Institut für Theoretische Physik II, Heinrich-Heine-Universität Düsseldorf Universitätsstraße 1, D-40225 Düsseldorf, Germany

(Received 17 May 2002; accepted in final form 25 November 2002)

Abstract
Brownian-dynamics computer simulations show a dynamical crossover in a strongly interacting colloidal suspension consisting of oppositely driven particles, wherein a uniform state transforms, with increasing driving force, into a locally demixed state characterized by strongly anisotropic stripe-like domains which are homogeneous in the direction parallel to the drive but have finite spatial extent of a double-correlation length in the transverse direction. A phenomenological dynamic density-functional theory has been proposed which accounts for such a strongly anisotropic state as arising from an instability of a homogeneous state.

PACS
82.70.-y - Disperse systems; complex fluids.
61.20.-p - Structure of liquids.
05.40.-a - Fluctuation phenomena, random processes, noise, and Brownian motion.

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