We investigate the formation of misfit dislocations in strained heteroepitaxial crystal growth and their influence on the structure of the growing layers. We use Kinetic Monte Carlo simulations for an off-lattice model in 1+1 dimensions with Lennard-Jones interactions. Two different types of the formation of dislocations are found, depending on the sign and the magnitude of the misfit. Misfit d...

The dominant mechanism for creating large irreversible strain in atomic crystals is the motion of dislocations, a class of line defects in the crystalline lattice. Here we show that the motion of dislocations can also be observed in strained colloidal crystals, allowing detailed investigation of their topology and propagation. We describe a laser diffraction microscopy setup used to study the g...

We study the mechanics and statistical physics of dislocations interacting on cylinders, motivated by the elongation of rod-shaped bacterial cell walls and cylindrical assemblies of colloidal particles subject to external stresses. The interaction energy and forces between dislocations are solved analytically, and analyzed asymptotically. The results of continuum elastic theory agree well with ...

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Sakari Sintonen Name of the doctoral dissertation Synchrotron radiation x-ray topography of crystallographic defects in GaN Publisher School of Electrical Engineering Unit Department of Microand Nanosciences Series Aalto University publication series DOCTORAL DISSERTATIONS 187/2014 Field of research Nanotechnology Manuscript s...

BACKGROUND CONTEXT Cervical spine dislocations represent an area of great controversy among spine surgeons. PURPOSE The purpose of this review is to present the specific areas of controversy and to provide a review of the literature. STUDY DESIGN A case of cervical spine dislocation is presented to illustrate the major controversies related to the treatment of cervical spine dislocations. ...

We consider a variational antiplane lattice model and demonstrate that at zero temperature, there exist locally stable states containing screw dislocations, given conditions on the distance between the dislocations and on the distance between dislocations and the boundary of the crystal. In proving our results, we introduce approximate solutions which are taken from the theory of dislocations i...

We propose and analyze a simple variational model for dislocations at semi-coherent interfaces. The energy functional describes the competition between two terms: a surface energy induced by dislocations and a bulk elastic energy, spent to decrease the amount of dislocations needed to compensate the lattice misfit. We prove that, for minimizers, the former scales like the surface area of the in...

Epitaxial Ba0.6Sr0.4TiO3 films were grown onto ~001! LaAlO3 by pulsed-laser deposition, and the dislocation structures of the films were investigated using transmission electron microscopy. Misfit dislocations with a periodicity of about 7 nm and Burgers vectors b5a^100& were observed at the interface. A high density of threading dislocations was present the films and these also had b 5a^100& ....