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Title:Some problems in the theory of crystalline surfaces
Author(s):Stewart, John Charles
Doctoral Committee Chair(s):Goldenfeld, Nigel D.
Department / Program:Physics
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Physics, General
Physics, Condensed Matter
Abstract:This thesis is concerned with the statics and dynamics of free crystalline surfaces. Both unstable and relaxational dynamics are treated with particular attention paid to elastic interactions. An equation of motion for the thermal faceting of an unstable planar crystalline surface is proposed, from which the behavior in the linear region of the surface structure function, initial domain size, and velocity of domain spreading are extracted. Elastic interactions are shown to modify the location of the spinodal line significantly.
Solutions for the dynamics of the evaporative decay of one-dimensional sine waves, isolated step packets, and isolated facets on surfaces below their roughening transition are presented, which have only the initial time as a free parameter. The solutions are tested against mesoscopic models with excellent agreement found. Intrinsic and reconstruction-driven isolated facet growth are identified as distinct processes, with different equations of motion. The decay of a sine wave is shown to generate a far from equilibrium layer at the top of the sine wave, which has to be separated as a boundary layer.
The late stages of thermal faceting of a vicinal surface are shown to lead to a spontaneous breakdown of the coarse-grained free energy. Finite size effects and interface energies resulting from elastic interactions are calculated. Elastic interactions are shown to freeze one-dimensional domain ripening in thermal faceting at late times. The elastic displacement field and the corresponding stress and strain tensors of an isolated step are computed and used to measure the surface dipole moments of Si as: $d\sb{x}$ = 1.46eV/A and $d\sb{z}$ = 0.58eV/A. The displacement field of a stepped surface is computed. Surface steps on Pb are shown to melt due to the elastic field of a step and as a local wetting transition. The melting of steps, vacancies, and diffusers is shown to account for the anomalous behavior of the Pb equilibrium crystal shape.
Issue Date:1994
Rights Information:Copyright 1994 Stewart, John Charles
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9512562
OCLC Identifier:(UMI)AAI9512562

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