The effect of electrically active VGa–ON threading edge dislocations on drift and Hall mobilities in n-type epitaxial wurtzite WZ GaN is investigated theoretically. The charge distribution along the dislocation core is first obtained by means of a density-functional theory atomistic calculation; the two N atoms near the missing Ga atom at the dislocation core are found to be electron acceptors....

Abstract This work presents a regularized eigenstrain formulation around the slip plane of dislocations and resultant non-singular solutions for various dislocation configurations. Moreover, we derive generalized Eshelby stress tensor configurational force theory in context proposed model. Based on finite element formulation, calculate driving configurations, including single edge/screw disloca...

In this work, a novel method is put forward to quantitatively simulate the subsurface damages microstructural alteration of titanium alloy components subjected to microscale cutting. A trans-scale numerical framework is conducted with the purpose of revealing the underlying influence mechanism of tool structure parameters on subsurface dislocation configurations using a dislocation dynamics-bas...

The interaction between an edge dislocation and a crack in the presence of uniform applied tension and shear is considered. Emphasis is placed on the effects of partial closure and crack-face friction. Representative results are given.

The defect structure onattice-mismatched I-pm InxGal_xAs X 10-3) epilayers on GaAs was studied with scanning cathodoluminescence (CL), transmission electron microscopy (TEM), high-voltage electron microscopy, and scanning electron microscopy. CL shows that nonradiative recombination lines exist in the GaAs buffer layer as far as 4000 A from the interface. The density of these defects is indepen...

We study the excitation of harmonic waves in thin elastic samples by a single dislocation in arbitrary motion. We consider both screw and edge dislocations that move perpendicularly to the surfaces of the layer. In Fourier space the displacement velocity and dynamic stress fields generated by the motion of the dislocations are factored as the product of two terms: one depends on the motion of t...

Oxide dispersion strengthened (ODS) steels are promising candidates for applications in fusion and fission rectors. Y2O3 particles dispersed in an iron matrix drastically improve the strength without adverse effects on ductility. We investigate here details of the dislocation core structure in Y2O3 precipitates, and at the interface between the iron matrix and the Y2O3 precipitate. We also simu...

We report on the first direct nanoscale imaging of elementary edge dislocations in a thermotropic smectic-C* liquid crystal with the Burgers vector equal to one smectic layer spacing d. We find two different types of dislocation profiles. In the dislocation of type A, the layers deformations lack mirror symmetry with respect to the plane perpendicular to the Burgers vector; the dislocation core...

Screw dislocations play an important role in materials' mechanical, electrical and optical properties. However, imaging the atomic displacements in screw dislocations remains challenging. Although advanced electron microscopy techniques have allowed atomic-scale characterization of edge dislocations from the conventional end-on view, for screw dislocations, the atoms are predominantly displaced...