TY - JOUR

T1 - Competition between domain growth and interfacial melting

AU - Besold, Gerhard

AU - Mouritsen, Ole G.

PY - 2000/8/1

Y1 - 2000/8/1

N2 - We study domain growth and interfacial melting in a two-dimensional lattice-gas model by means of Monte Carlo simulation, using the grand-canonical ensemble. The model exhibits two classes of "solid" domains with superstructure unit cells of different orientation with respect to the underlying square lattice. Interfacial melting (grain-boundary melting) is only observed for grain-boundaries between domains of different orientation. For a constrained configuration of two domains of different orientation ("bicrystal"), separated by a single interface in the [1 1] direction, we find a logarithmic divergence of the width of the disordered wetting layer in accordance with predictions from mean-field theory. Domain growth in an unconstrained and initially disordered system, following a (down-)quench to temperatures well below the bulk melting temperature Tm, is found to be described by the the Lifshitz-Allen-Cahn growth law with exponent n = 1/2. With increasing quench temperature, a transition from non-activated continuous ordering to an activated nucleation-and-growth mechanism is observed. For quenches to temperatures only slightly below Tm, domain growth turns out to be effectively suppressed. When not yet equilibrated multi-domain configurations are up-quenched to and annealed at temperatures slightly below Tm, the further evolution of the system depends on the morphology of the domain pattern: an equilibrium mono-domain configuration is eventually obtained only if domains of the same orientation were initially present. For initial configurations with domains of both types of orientation, however, and depending on the actual domain sizes, interfacial melting may again drive the system towards a completely disordered, long-living metastable state.

AB - We study domain growth and interfacial melting in a two-dimensional lattice-gas model by means of Monte Carlo simulation, using the grand-canonical ensemble. The model exhibits two classes of "solid" domains with superstructure unit cells of different orientation with respect to the underlying square lattice. Interfacial melting (grain-boundary melting) is only observed for grain-boundaries between domains of different orientation. For a constrained configuration of two domains of different orientation ("bicrystal"), separated by a single interface in the [1 1] direction, we find a logarithmic divergence of the width of the disordered wetting layer in accordance with predictions from mean-field theory. Domain growth in an unconstrained and initially disordered system, following a (down-)quench to temperatures well below the bulk melting temperature Tm, is found to be described by the the Lifshitz-Allen-Cahn growth law with exponent n = 1/2. With increasing quench temperature, a transition from non-activated continuous ordering to an activated nucleation-and-growth mechanism is observed. For quenches to temperatures only slightly below Tm, domain growth turns out to be effectively suppressed. When not yet equilibrated multi-domain configurations are up-quenched to and annealed at temperatures slightly below Tm, the further evolution of the system depends on the morphology of the domain pattern: an equilibrium mono-domain configuration is eventually obtained only if domains of the same orientation were initially present. For initial configurations with domains of both types of orientation, however, and depending on the actual domain sizes, interfacial melting may again drive the system towards a completely disordered, long-living metastable state.

KW - Complete wetting

KW - Continuous ordering

KW - Domain growth kinetics

KW - Grain-boundaries

KW - Interfacial melting

KW - Lattice-gas models

KW - Monte Carlo simulation

KW - Nucleation-and-growth

KW - Solid-liquid transition

UR - http://www.scopus.com/inward/record.url?scp=0346106368&partnerID=8YFLogxK

M3 - Journal article

AN - SCOPUS:0346106368

VL - 18

SP - 225

EP - 244

JO - Computational Materials Science

JF - Computational Materials Science

SN - 0927-0256

IS - 2

ER -