The low-temperature phase and melting of a dilute, binary, two-dimensional array of colloidal particles with dipolar interactions are studied. The system consists of a 1% concentration of larger particles in an otherwise monodispersed array of polymer spheres confined between two glass plates. The translational and bond-orientational correlations in the condensed phase are those of a quenched hexatic glass with dislocations pinned to the larger particles. Melting into the fluid phase is consistent with the disclination-pair-dissociation-mediated theory of melting.

• Received 21 October 1993

DOI:https://doi.org/10.1103/PhysRevB.49.9190