# Dresden 2009 – wissenschaftliches Programm

## Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

# DY: Fachverband Dynamik und Statistische Physik

## DY 12: Poster I

### DY 12.33: Poster

### Dienstag, 24. März 2009, 14:30–16:30, P1A

**Computer simulations of 2D colloidal crystals: elastic constants and effects of periodic, external fields** — •Kerstin Franzrahe and Peter Nielaba — Department of Physics, University of Konstanz, 78457 Konstanz, Germany

Minimization trends in physics and technology have caused a lot of interest in monolayers and their interactions with a substrate lately. Colloidal suspensions have proven to be ideal model systems for studies on such systems. The question of how the addition of another length scale into such a system will influence the intricate competition between adsorbate-adsorbate interaction and adsorbate-substrate interaction is addressed by studying a binary 50% hard disk mixture under the influence of a 1D spatially periodic substrate potential. The phase diagram is investigated by Monte Carlo simulations[1,3]. Furthermore we analyze the elastic properties of two dimensional colloidal crystals. The nonlocal elastic response function is crucial for understanding many properties of soft solids. It may be obtained by measuring strain-strain autocorrelation functions. We use computer simulations as well as video microscopy data of superparamagnetic colloids to obtain these correlations for two-dimensional triangular solids. Elastic constants and elastic correlation lengths are extracted by analyzing the correlation functions[2,3].

[1] K. Franzrahe, P. Nielaba, Phys. Rev. E 76, 061503 (2007); [2] K. Franzrahe, P. Keim, G. Maret, P. Nielaba and S. Sengupta, Phys. Rev. E 78, 026106 (2008); [3] K. Franzrahe et al., J. Phys.: Condens. Matter 20, 404218 (2008)