We consider a static theory of dislocations with moment stress in an anisotropic or isotropic elastoplastical material as a T (3)-gauge theory. We obtain Yang-Mills type field equations which express the force and the moment equilibrium. Additionally, we discuss several constitutive laws between the dislocation density and the moment stress. For a straight screw dislocation, we find the stress ...

2014 The concept of the Boyer-Hardy source-force, or Kanzaki force, for a static screw dislocation is extended to describe a moving dislocation 2014 in a simple cubic, nearest neighbour, harmonic lattice (snapping-bond model) 2014 and together with the phonon Green’s function is used to derive expressions for the atomic displacements and timeaveraged energy disspation, viz. the rate of energy t...

2014 We consider a lattice dynamics model of a straight screw dislocation moving in a simple cubic lattice with nearest-neighbour « snapping bonds ». The effect on the lattice of the dislocation motion is described by a dynamic source-force, or Kanzaki-force, and the lattice response by the phonon Green’s function. A random array of isotopic substitutional point defects is introduced, and the a...

Local recombination properties of threading screw and edge dislocations in 4H–SiC epitaxial layers have been studied using electron beam induced current !EBIC". The minority carrier diffusion length in the vicinity of dislocations was found to vary with dislocation type. Screw dislocations had a more pronounced impact on diffusion length than the edge dislocations, evidencing stronger recombina...

An infinite plane problem with a circular boundary under the screw dislocation is solved by using a new method. The angle-based fundamental solution for screw dislocation is expanded into degenerate kernel. Our method can explain why the image screw dislocation is required. Besides, the location of the image point can be obtained easily by using degenerate kernel after satisfying boundary condi...

The dislocation widths, Peierls barriers and Peierls stresses for shuffle screw dislocations in diamond structure crystals, Si and Ge, have been calculated by the improved P-N theory. The widths are about 0.6b, where b is the Burgers vector. The Peierls barrier for shuffle screw dislocation in Si and Ge, is about 3.61~4.61meV/Å and 5.31~13.32meV/Å, respectively. The Peierls stress is about 0.28...

A review is given of the results of first principles calculations used to investigate the structures and electronic properties of screw and edge dislocations in GaN. The atoms at the core of the full core screw dislocation possess heavily strained bonds leading to deep gap states. Removing the first shell of Ga and N atoms gives a screw dislocation with a small open core consisting of f10 10g t...

Dislocations are a common type of defects that signifi cantly infl uence many mechanical phenomena such as plastic deformation, crystal growth, morphology, or diffusion of materials. Although dislocations have been well-studied for simple crystalline structures such as pure metals, semiconductors, ionic materials, and binary oxides, there is very limited knowledge on such defects in complex-lay...

BACKGROUND Appropriate treatment of acromioclavicular joint dislocation is controversial. Acroplate fixation is one of the most common treatment methods of acromioclavicular joint (ACJ) dislocation. Based on the risk of re-dislocation after Acroplate fixation, we assumed that combined fixation with an Acroplate and a coracoclavicular screw helps improve the outcome. OBJECTIVES The main purpos...

We consider an exact reduction of a model of Field Dislocation Mechanics to a scalar problem in one spatial dimension and investigate the existence of static and slow, rigidly moving single or collections of planar screw dislocation walls in this setting. Two classes of drag coefficient functions are considered, namely those with linear growth near the origin and those with constant or more gen...