Systematic approach for determination of equilibrium atomic surface structure

Joanna Millunchick

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joannamm@umich.edu

2014 HH Dow

T: (734) 647-8980

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John C Thomas, Norm Modine, A, Joanna M Millunchick, and der VA Van (2010)

PHYSICAL REVIEW B, 82(16).

Despite the increasing importance of atomic-scale surfacecharacterization, the state of the art in automating the prediction ofatomic surface structure lags behind recent advances in bulk structureprediction. In this paper we present an approach whereby poorlycharacterized equilibrium surface structure can be systematicallydetermined via a two-step process and apply this approach to the GaAs(001) surface. First we demonstrate that trends in complex surfacestructure are reducible to a small set of basic structural rules whichcan then be used to efficiently generate many likely surfacereconstruction prototypes. Second we use first-principles energycalculations to screen for low-energy prototypes and apply the clusterexpansion formalism to explore the effect of configurational excitationsat surface sites capable of low-energy species substitution. Using thismethod, we generate a database of all likely reconstruction prototypesfor the group-V-rich III-V (001) surface, which is then used to obtainthe GaAs(001) reconstruction phase diagram from first principles. Wealso identify a class of (4 x 3) reconstructions that is nearly stableon pure GaAs and is likely important in kinetically limited growthregimes and on strain-stabilized III-V alloy surfaces.

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