Effect of Dipolar Interaction in Molecular Crystals
| Autor: | Hoang, Danh-Tai, Diep, Hung The |
|---|---|
| Přispěvatelé: | Laboratoire de Physique Théorique et Modélisation (LPTM - UMR 8089), Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Diep, Hung |
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
[PHYS.COND.CM-SM] Physics [physics]/Condensed Matter [cond-mat]/Statistical Mechanics [cond-mat.stat-mech]
Dipolar Interaction Monte Carlo Simulation PACS: 61.30.Cz 64.70.M [PHYS.COND.CM-SM]Physics [physics]/Condensed Matter [cond-mat]/Statistical Mechanics [cond-mat.stat-mech] Molecular Crystals Potts Model Phase Transition |
| Popis: | We investigate in this paper the ground state and the nature of the transition from an orientational ordered phase at low temperature to the disordered state at high temperature in a molecular crystal. Our model is a Potts model which takes into account the exchange interaction $J$ between nearest-neighbor molecules and a dipolar interaction between molecular axes in three dimensions. The dipolar interaction is characterized by two parameters: its amplitude $D$ and the cutoff distance $r_c$. If the molecular axis at a lattice site has three orientations, say the $x$, $y$ or $z$ axes, then when $D=0$, the system is equivalent to the 3-state Potts model: the transition to the disordered phase is known to be of first order. When $D\neq 0$, the ground-state configuration is shown to be composed of two independent interpenetrating layered subsystems which form a sandwich whose periodicity depends on $D$ and $r_c$. We show by extensive Monte Carlo simulation with a histogram method that the phase transition remains of first order at relatively large values of $r_c$. |
| Databáze: | OpenAIRE |
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