Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.649778
Title: Computer simulation of two-dimensional condensed matter systems
Author: Duncan, Peter D.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2006
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Abstract:
Motivated by the large diversity of two dimensional condensed matter systems, various two dimensional models were studied using computer simulation. The structure and dynamics in a monolayer of dipolar soft spheres were studied using Molecular Dynamics simulation. This is a model for colloidal ferrofluids. Langevin Dynamics simulations have been employed to study the aggregate kinetics of the dipolar chains and rings starting from a ‘random’ configuration. Clusters were identified using an energy criterion, and classified as chains, rings or defect clusters. The mechanisms by which these clusters form are discussed. At high density, there is a high transient concentration of defects, indicating an interconnected network structure. This suggests that the phase transition proposed by Tlusty and Safran [Tlusty and Safran, Science 290, 1328 (2000)] could be recovered as a metastable phase transition if the system could be kinetically trapped in this transient state. The dynamics of antiferromagnetically coupled Heisenberg spins on a kagomé lattice has been studied using numerical simulation. This system is highly frustrated – the lattice places competing constraints on the spins. We investigate the effect of breaking bonds in the lattice, which relieves the frustration to a certain extent. The phase diagram of a two dimensional system of hard disk trimers has been explored by Monte Carlo simulation. This might serve as a coarse grained model for the aggregation of proteins in a biological membrane. Many proteins are roughly triangular in shape or form trimeric units. The model consists of three hard disks fused together in a triangular arrangement. One of the disks interacts with the corresponding disk on other trimers via a square-well potential, representing specific interactions between the protein molecules. In the fluid phase at low density the trimers form aggregates containing typically four to six trimers. In the solid phase, the trimers pack such that individual disks are on a triangular lattice. There are different possible packings of the trimers consistent with this packing of individual disks.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.649778  DOI: Not available
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