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DY: Fachverband Dynamik und Statistische Physik
DY 41: Poster - Pattern/ Nonlinear Dyn./ Fluids/ Granular/ Critical Phen.
DY 41.40: Poster
Thursday, April 3, 2014, 17:00–19:00, P3
Melting of 2D solids under quenched disorder — •Sven Deutschländer1, Tobias Horn2, Hartmut Löwen2, Georg Maret1, and Peter Keim1 — 1Fachbereich Physik, Universität Konstanz, 78464 Konstanz, Germany — 2Institut für Theoretische Physik II, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
We investigate the effect of quenched random disorder on the melting transition of two-dimensional solids providing both colloidal experiments and monte carlo simulations of parallel repulsive dipols [1]. According to the KTHNY theory, we observe a two step melting process with an intermediate hexatic phase and studying the orientational order and correlation, we are able to investigate the detailed phase behavior for weak disorder strengths. By determining orientational correlation times and Frank's constant, we show that the solid-hexatic phase transition is strongly influenced by pinning, while the hexatic-isotropic transition remains rather unaffected. This is in agreement with theoretical predictions for solids with quenched random disorder, first discussed by D. R. Nelson and later by M.-C. Cha and H. A. Fertig. In addition, we observe critical-like orientational fluctuations on large time scales. These fluctuations are consistent with the continuous nature of the phase transitions and not locally affected by quenched disorder .
[1] S. Deutschländer, T. Kruppa, H. Löwen, G. Maret, and P. Keim, Phys. Rev. Lett. 111, 098301 (2013)