Berlin 2015 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 70: Complex Fluids and Soft Matter - Part III (joint session DY, CPP, BP)
CPP 70.1: Hauptvortrag
Donnerstag, 19. März 2015, 15:00–15:30, BH-N 334
Melting of soft disks: From liquid-hexatic coexistence to continuous transitions — •Sebastian C. Kapfer1,2, Manon Michel2, and Werner Krauth2 — 1Theoretische Physik 1, FAU Erlangen, Germany — 2LPS, Ecole normale supérieure, Paris, France
The melting transition of two-dimensional solids has been a subject of continued research for more than fifty years, with the prevalent scenarios being the KTHNY theory of defect unbindung and a conventional first-order liquid-solid transition. For hard disks, the KTHNY scenario has recently been essentially confirmed, even though the liquid-hexatic step is of first order [1]. Using a new rejection-free global-balance Monte Carlo algorithm [2], we show that this result transfers to soft interactions with inverse power-law or Yukawa potentials [3]. The order of the liquid-hexatic step can be tuned from first-order to continuous by softening the potential. We show that there is always a hexatic phase separating the liquid and solid phases, and identify two regimes of the hexatic with vastly different correlation lengths. These results rationalize a plethora of simulation results obtained in the past, and could be verified in charged-colloid experiments.
[1] E. P. Bernard, W. Krauth, Phys. Rev. Lett. 107, 155704 (2011). [2] M. Michel, S. C. Kapfer and W. Krauth, JCP 140, 054116 (2014). [3] S. C. Kapfer, W. Krauth, preprint at arXiv:1406.7224.