Inferring planar disorder in close-packed structures via e-machine spectral reconstruction theory: Examples from simulated diffraction spectra

Dowman P. Varn
Max-Planck-Institut für Physik komplexer Systeme
Santa Fe Institute
Department of Physics and Astromony, University of Tennessee, Knoxville

Geoffrey S. Canright
Telenor Research and Development
Department of Physics and Astronomy, University of Tennessee, Knoxville

James P. Crutchfield
Computational Science & Engineering Center & Physics Department, University of California, Davis
Santa Fe Institute



Abstract:

Previously we detailed a novel algorithm, e-machine spectral reconstruction theory (eMSR), that infers pattern and disorder in planar-faulted, close-packed structures directly from X-ray diffraction spectra [Varn, Canright & Crutchfield, submitted to Acta Crystallographica A]. Here we apply eMSR to simulated diffraction spectra from five close-packed crystals. We find that for stacking structures with a memory length of three or less, eMSR reproduces the statistics of the stacking structure; the result being in the form of a directed graph called an e-machine. For stacking structures with a memory length larger than three, eMSR returns a model that captures many important features of the original stacking structure. These include multiple stacking faults and multiple crystal structures. Further, we find that eMSR is able to discover stacking structure in even highly disordered crystals. In order to address issues concerning the long range order observed in many classes of layered materials, we define several length parameters calculable from the e-machine, and discuss their relevance.

A copy of this paper in pdf format: Inferring planar disorder in close-packed structures via e-machine spectral reconstruction theory: Examples from simulated diffraction spectra


Citation: D.P. Varn, G. S. Canright and J.P. Crutchfield, submitted to Journal of Statistical Mechanics

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Last updated: 26 April 2009. Copyright © 2008-2009 by Dowman P. Varn. Contact: dpv@ComplexMatter.org

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