Dresden 2006 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.72: Poster

Donnerstag, 30. März 2006, 16:00–18:00, P1

Colloidal 2d-transport in restricted geometrie — •Michael Köppl , Artur Erbe, and Paul Leiderer — Universität Konstanz, FB Physik, Universitätsstr. 10, 78467 Konstanz

Colloidal particles can be used as model systems for the behavior of atomic or nanometer scale sized objects. Thermal energies of the particles in solution are of the same order of magnitudes as typical interparticle interactions. This leads to mesoscopic behavior. On the other hand, classical systems like cars on a motorway or pedestrians on a walkway can be modelled as well. In this work we study the transport of colloidal particles (4.7 µm in diameter) through narrow constrictions on the scale of 60 − 100 µm. The behavior of these systems shows similarities to current transport in mesoscopic wires or electron transport on Helium surfaces. We create additional potential barriers by application of focused light fields (laser tweezing or repulsion of the particles by the light fields) on the particle ensemble. Transport through these barriers can be tuned by changing the interparticle interactions and the height of the potential barriers. We typically use superparamagnetic particles in our experiments. Thus the interactions between the particles depend quadratically on an externally applied magnetic field for low fields. An increase in magnetic field leads to a change form a liquid phase to a crystalline phase. The influence of this change on the transport behavior of the system is studied in detail.