title: Low-density ordered phase in brownian dipolar colloidal suspensions.
abstract: We study the low volume fraction and electric field phase behavior of a Brownian colloidal suspension. On the application of a uniform ac field, we find a novel phase where chains of particles aggregate to form a well defined cellular network, consisting of particle-free "voids" surrounded by a percolating network of particle-rich walls. This cellular structure is stable to very long times, indicative of an equilibrium thermodynamic phase. The cell-cell spacing is not sensitive to the concentration of the sample but scales with sample thickness. Any self-consistent mechanism for the existence of this void phase must consist of long-ranged repulsions and shorter-ranged attractions.
authors.affiliation: Department of Physics and Physical Oceanography, Memorial University, St. John's, Newfoundland and Labrador, A1B 3X7, Canada. amit@mun.ca
authors.forename: Amit K
authors.initials: AK
authors.lastname: Agarwal
authors.forename: Anand
authors.initials: A
authors.lastname: Yethiraj