title: Anisotropic mean-square displacements in two-dimensional colloidal crystals of tilted dipoles.
abstract: Superparamagnetic colloidal particles confined to a flat horizontal air-water interface in an external magnetic field, which is tilted relative to the interface, form anisotropic two-dimensional crystals resulting from their mutual dipole-dipole interactions. Using real-space experiments and harmonic lattice theory we explore the mean-square displacements of the particles in the directions parallel and perpendicular to the in-plane component of the external magnetic field as a function of the tilt angle. We find that the anisotropy of the mean-square displacement behaves nonmonotonically as a function of the tilt angle and does not correlate with the structural anisotropy of the crystal.
authors.affiliation: Institut für Theoretische Physik II, Heinrich-Heine-Universität Düsseldorf, Germany.
authors.forename: V A
authors.initials: VA
authors.lastname: Froltsov
authors.forename: C N
authors.initials: CN
authors.lastname: Likos
authors.forename: H
authors.initials: H
authors.lastname: Löwen
authors.forename: C
authors.initials: C
authors.lastname: Eisenmann
authors.forename: U
authors.initials: U
authors.lastname: Gasser
authors.forename: P
authors.initials: P
authors.lastname: Keim
authors.forename: G
authors.initials: G
authors.lastname: Maret