Anisotropy induced crossover from weakly to strongly first order melting of two dimensional solids

Singh, Rakesh S and Santra, Mantu and Bagchi, Biman (2013) Anisotropy induced crossover from weakly to strongly first order melting of two dimensional solids. In: Journal of Chemical Physics, 138 (18). 184507_1-184507_9.

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Abstract

Melting and freezing transitions in two dimensional (2D) systems are known to show highly unusual characteristics. Most of the earlier studies considered atomic systems: the melting of 2D molecular solids is still largely unexplored. In order to understand the role of anisotropy as well as multiple energy and length scales present in molecular systems, here we report computer simulation studies of melting of 2D molecular systems. We computed a limited portion of the solid-liquid phase diagram. We find that the interplay between the strength of isotropic and anisotropic interactions can give rise to rich phase diagram consisting of isotropic liquid and two crystalline phases-honeycomb and oblique. The nature of the transition depends on the relative strength of the anisotropic interaction and a strongly first order melting turns into a weakly first order transition on increasing the strength of the isotropic interaction. This crossover can be attributed to an increase in stiffness of the solid phase free energy minimum on increasing the strength of the anisotropic interaction. The defects involved in melting of molecular systems are quite different from those known for the atomic systems.

Item Type:	Journal Article
Publication:	Journal of Chemical Physics
Publisher:	American Institute of Physics
Additional Information:	Copyright of this article belongs to American Institute of Physics.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	05 Jul 2013 05:52
Last Modified:	05 Jul 2013 05:52
URI:	http://eprints.iisc.ac.in/id/eprint/46787

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