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Title: The stability of elastically strained nanorings and the formation of quantum dot molecules
Authors: Gill, Simon P.A.
First Published: 11-Feb-2015
Publisher: Elsevier
Citation: Simon P.A. Gill, The stability of elastically strained nanorings and the formation of quantum dot molecules, Journal of the Mechanics and Physics of Solids
Abstract: Self-assembled nanorings have recently been identified in a number of heteroepitaxially strained material systems. Under some circumstances these rings have been observed to break up into ringshaped quantum dot molecules. A general non-linear model for the elastic strain energy of nonaxisymmetric epitaxially strained nanostructures beyond the small slope assumption is developed. This model is then used to investigate the stability of strained nanorings evolving via surface diffusion subject to perturbations around their circumference. An expression for the fastest growing mode is determined and related to experimental observations. The model predicts a region of stability for rings below a critical radius, and also a region for larger rings which have a proportionally small thickness. The predictions of the model are shown to be consistent with the available results. For the heteroepitaxial InP on In0.5Ga0.5P system investigated by Jevasuwan et al. (2013), the nanorings are found to be stable below a certain critical size. This is in good quantitative agreement with the model predictions. At larger sizes, the rings are unstable. The number of dots in the resulting quantum dot molecule is similar to the mode number for the fastest growing mode. Second order terms show that the number of dots is expected to reduce as the height of the ring increases in proportion to its thickness. The strained In0.4Ga0.6As on GaAs nanorings of Hanke et al (2007) are always stable and this is in accordance with the findings of the analysis. The Au nanorings of Ruffino et al. (2011) are stable as well, even as they expand during annealing. This observation is also shown to be consistent with the proposed model, which is expected to be useful in the design and tailoring of heteroepitaxial systems for the self-organisation of quantum dot molecules.
DOI Link: 10.1016/j.jmps.2015.02.009
ISSN: 0022-5096
Version: Post-print
Status: Peer-reviewed
Type: Journal Article
Rights: NOTICE: this is the author’s version of a work that was accepted for publication in Journal of the Mechanics and Physics of Solids. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of the Mechanics and Physics of Solids, 2015 DOI 10.1016/j.jmps.2015.02.009
Appears in Collections:Published Articles, Dept. of Engineering

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