%0 Book Section %1 statphys23_0352 %A Muller, M. %A Milchev, A. %A Binder, K. %A Landau, D.P. %B Abstract Book of the XXIII IUPAP International Conference on Statistical Physics %C Genova, Italy %D 2007 %E Pietronero, Luciano %E Loreto, Vittorio %E Zapperi, Stefano %K computer confinement fluctuations interface phase simulation statphys23 topic-6 transitions wetting %T Phase transitions and interface fluctuations in double wedges and pyramides with competing surface fields %U http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=352 %X The interplay between surface and interface effects on the phase transition of binary AB mixtures that are confined into unconventional geometries is investigated by Monte Carlo simulations and phenomenological scaling considerations. Both double-wedge and bi-pyramid confinements are considered and competing surface fields are applied at the two opposing halves of the system. Below the bulk critical temperature of the AB mixture, domains of opposite order parameter are stabilized at the corresponding corners and an interface runs across the middle, basal plane of the bipartite geometry. The order parameter remains zero. Upon decreasing the temperature further, however, one encounters a phase transition at which the AB symmetry is broken, the interface is localized in one of the two wedges or pyramids, respectively, and the order parameter is finite. In both cases, the transition becomes discontinuous in the thermodynamic limit but is not a first-order phase transition. At the transition the fluctuations of the interface become comparable to the system size. In a antisymmetric double-wedge geometry (a pore with extension $L L L_y$) the transition is closely related to the wedge-filling transition. Choosing the ratio of the cross-section $L L$ of the double-wedge and its length $L_y$ according to $ L_y/L^3=$ const, simulations and phenomenological consideration show that the new type of phase transition is characterized by critical exponents $\alpha=3/4$, $\beta=0$, and $\gamma=5/4$ for the specific heat, order parameter, and susceptibility, respectively. The findings corroborate Parry's predictions for the filling transition of a wedge and we provide evidence from computer simulation that the transition can be observed even if is the wetting transition on a planar surface is of first order. In an antisymmetric bi-pyramid the transition occurs at the cone-filling transition of a single pyramid. The important critical fluctuations are associated with the fluctuations of the total magnetization and they can be described by a Landau-type free energy. Monte Carlo results provide evidence that the coefficients of the Landau-type free energy exhibit an unusual system-size dependence. This system-size dependence, in turn, gives rise to critical amplitudes that diverge with system size and result in a transition that becomes discontinuous in the thermodynamic limit.

@incollection{statphys23_0352, abstract = {The interplay between surface and interface effects on the phase transition of binary AB mixtures that are confined into unconventional geometries is investigated by Monte Carlo simulations and phenomenological scaling considerations. Both double-wedge and bi-pyramid confinements are considered and competing surface fields are applied at the two opposing halves of the system. Below the bulk critical temperature of the AB mixture, domains of opposite order parameter are stabilized at the corresponding corners and an interface runs across the middle, basal plane of the bipartite geometry. The order parameter remains zero. Upon decreasing the temperature further, however, one encounters a phase transition at which the AB symmetry is broken, the interface is localized in one of the two wedges or pyramids, respectively, and the order parameter is finite. In both cases, the transition becomes discontinuous in the thermodynamic limit but is not a first-order phase transition. At the transition the fluctuations of the interface become comparable to the system size. In a antisymmetric double-wedge geometry (a pore with extension $L \times L \times L_y$) the transition is closely related to the wedge-filling transition. Choosing the ratio of the cross-section $L \times L$ of the double-wedge and its length $L_y$ according to $ L_y/L^3=$ const, simulations and phenomenological consideration show that the new type of phase transition is characterized by critical exponents $\alpha=3/4$, $\beta=0$, and $\gamma=5/4$ for the specific heat, order parameter, and susceptibility, respectively. The findings corroborate Parry's predictions for the filling transition of a wedge and we provide evidence from computer simulation that the transition can be observed even if is the wetting transition on a planar surface is of first order. In an antisymmetric bi-pyramid the transition occurs at the cone-filling transition of a single pyramid. The important critical fluctuations are associated with the fluctuations of the total magnetization and they can be described by a Landau-type free energy. Monte Carlo results provide evidence that the coefficients of the Landau-type free energy exhibit an unusual system-size dependence. This system-size dependence, in turn, gives rise to critical amplitudes that diverge with system size and result in a transition that becomes discontinuous in the thermodynamic limit.}, added-at = {2007-06-20T10:16:09.000+0200}, address = {Genova, Italy}, author = {Muller, M. and Milchev, A. and Binder, K. and Landau, D.P.}, biburl = {https://www.bibsonomy.org/bibtex/2cc490d0039e265333de24f4e15faa766/statphys23}, booktitle = {Abstract Book of the XXIII IUPAP International Conference on Statistical Physics}, editor = {Pietronero, Luciano and Loreto, Vittorio and Zapperi, Stefano}, interhash = {712a4ccefa38ed7f24f859fea8cde5b3}, intrahash = {cc490d0039e265333de24f4e15faa766}, keywords = {computer confinement fluctuations interface phase simulation statphys23 topic-6 transitions wetting}, month = {9-13 July}, timestamp = {2007-06-20T10:16:18.000+0200}, title = {Phase transitions and interface fluctuations in double wedges and pyramides with competing surface fields}, url = {http://st23.statphys23.org/webservices/abstract/preview_pop.php?ID_PAPER=352}, year = 2007 }