Regensburg 2007 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 30: Poster II
DY 30.25: Poster
Donnerstag, 29. März 2007, 16:00–18:00, Poster D
Phase transitions in 2D colloidal crystals in presence of a 1D periodic potential — •Florian Bürzle and Peter Nielaba — Department of Physics, University of Konstanz, 78457 Konstanz, Germany
2D melting transitions for model colloids in presence of a 1D external periodic potential are investigated using Monte Carlo simulation, thereby extending former studies [1]. We modelled the colloidal dispersions by hard disks in the canonical ensemble. In particular, we explore a hard disk system with commensurability ratio p=√3as/2d=2, where as is the mean distance between the disks and d the period of the external potential. In this system one expects from theoretical considerations [2] a novel ’locked smectic’ phase between the well known locked floating solid and the modulated liquid. This new phase, which was also observed in a recent experimental study [3], has been verified in our simulations. Furthermore, we used various statistical quantities like order parameters, their cumulants and response functions, to obtain a phase diagram for the transitions between the three phases.
[1] W. Strepp, S. Sengupta, P. Nielaba, Phys. Rev. E 63, 046106 (2001)
[2] L. Radzihovsky, E. Frey, D. R. Nelson, Phys. Rev. E 63, 031503 (2001)
[3] J. Baumgartl, M. Brunner, C. Bechinger, Phys. Rev. Lett. 93, 168301 (2004)