Regensburg 2004 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 46: Poster
DY 46.84: Poster
Donnerstag, 11. März 2004, 16:00–18:00, Poster D
Commensurability effects of colloidal monolayers on hexagonally patterned substrates — •Stefan Bleil1, Matthias Brunner2, and Clemens Bechinger1 — 12. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart — 2Fachbereich Physik, Universität Konstanz, 78457 Konstanz
Colloidal suspensions are excellent model systems for investigations of phase transitions in two-dimensional (2D) systems. While most of the previous work concentrated on homogeneous substrates, much less is known about the phase behavior on patterned substrates although the latter closely resembles the behavior of atomic adsorbates on crystalline surfaces. In our experiments we mimic 2D patterned substrates for colloidal particles by the interference pattern of several laser beams which lead to triangular substrate potentials. We present results where the number density of charge stabilized colloidal particles was systematically varied. This allowed us to study the effect of the filling fraction η (i.e. the ratio between the number of colloidal particles and the number of substrate wells) on the observed structure of the colloidal system. Depending on the filling fraction we observe commensurate and incommensurate structures. We also compare our results with recent numerical simulations.