Honeycomb and triangular domain wall networks in heteroepitaxial systems

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Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2016-05-07
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Language
en
Pages
1-11
Series
Journal of Chemical Physics, Volume 144, issue 17
Abstract
A comprehensive study is presented for the influence of misfit strain, adhesion strength, and lattice symmetry on the complex Moiré patterns that form in ultrathin films of honeycomb symmetry adsorbed on compact triangular or honeycomb substrates. The method used is based on a complex Ginzburg-Landau model of the film that incorporates elastic strain energy and dislocations. The results indicate that different symmetries of the heteroepitaxial systems lead to distinct types of domain wall networks and phase transitions among various surface Moiré patterns and superstructures. More specifically, the results show a dramatic difference between the phase diagrams that emerge when a honeycomb film is adsorbed on substrates of honeycomb versus triangular symmetry. It is also shown that in the small deformation limit, the complex Ginzburg-Landau model reduces to a two-dimensional sine-Gordon free energy form. This free energy can be solved exactly for one dimensional patterns and reveals the role of domains walls and their crossings in determining the nature of the phase diagrams.
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Citation
Elder , K R , Chen , Z , Elder , K L M , Hirvonen , P , Mkhonta , S K , Ying , S C , Granato , E , Huang , Z F & Ala-Nissilä , T 2016 , ' Honeycomb and triangular domain wall networks in heteroepitaxial systems ' , Journal of Chemical Physics , vol. 144 , no. 17 , 174703 , pp. 1-11 . https://doi.org/10.1063/1.4948370