Large Scale Atomistic Simulation with Electrostatics: The Case of Cation Impurity Segregation Along an Edge Dislocation Line

2010 ◽  
Author(s):  
Feiwu Zhang ◽  
Kate Wright ◽  
Julian D. Gale ◽  
Andrew M. Walker
Keyword(s):  
Edge Dislocation ◽  
Atomistic Simulation ◽  
Large Scale ◽  
Dislocation Line ◽  
Impurity Segregation ◽  
Cation Impurity

Interaction between an edge dislocation near a circular void within the framework of the theory of strain gradient elasticity

2018 ◽  
Vol 27 (3-4) ◽  
Author(s):  
Kamyar Davoudi
Keyword(s):  
Edge Dislocation ◽  
Function Method ◽  
Dislocation Line ◽  
Gradient Elasticity ◽  
Image Force ◽  
Strain Gradient Elasticity ◽  
Gradient Solution ◽  
Stress Function Method ◽  
Classical Size ◽  
Isotropic Theory

AbstractThe purpose of this paper was to consider an edge dislocation near a circular hole within the isotropic theory of gradient elasticity. The stress field is derived with the help of a stress function method. The gradient stresses possess no singularity at the dislocation line. As a result, the image force exerted on the dislocation due to the presence of the hole remains finite when the dislocation approaches the interface. The gradient solution demonstrates a non-classical size effect.

On the features of dislocation–obstacle interaction in thin films: large-scale atomistic simulation

2006 ◽  
Vol 86 (8) ◽  
pp. 511-519 ◽  
Author(s):  
Y. N. Osetsky ◽  
Y. Matsukawa ◽  
R. E. Stoller ◽  
S. J. Zinkle
Keyword(s):  
Thin Films ◽  
Atomistic Simulation ◽  
Large Scale

Simple Flexible Boundary Conditions for the Atomistic Simulation of Dislocation Core Structure and Motion

1992 ◽  
Vol 291 ◽  
Author(s):  
Roberto Pasianot ◽  
Eduardo J. Savino ◽  
Zhao-Yang Xie ◽  
Diana Farkas
Keyword(s):  
Atomistic Simulation ◽  
Dislocation Line ◽  
Dislocation Core ◽  
Dislocation Motion ◽  
Peierls Stress ◽  
Rigid Boundary ◽  
The Past ◽  
Structure And Motion ◽  
Linear Effects ◽  
Dislocation Core Structure

ABSTRACTFlexible boundary codes for the atomistic simulation of dislocations and other defects have been developed in the past mainly by Sinclair [1], Gehlen et al.[2], and Sinclair et al.[3]. These codes permitted the use of smaller atomic arrays than rigid boundary codes, gave descriptions of core non-linear effects and allowed fair assessments of the Peierls stress for dislocation motion. Green functions (continuum or discrete) or surface traction forces were used to relax the boundary atoms.A much simpler approach is followed here. Core and mobility effects at the boundary are accounted for by a dipole tensor centered at the dislocation line, whose components constitute six more parameters of the minimization process. Results are presented for [100] dislocations in NiAl. It is shown that, within the limitations of the technique, reliable values of the Peierls stress are obtained.

Large-scale atomistic simulation of a nanosized fibril formed by thiophene–peptide “molecular chimeras”

Soft Matter ◽  
2010 ◽  
Vol 6 (7) ◽  
pp. 1453 ◽  
Author(s):  
Alexey K. Shaytan ◽  
Alexei R. Khokhlov ◽  
Pavel G. Khalatur
Keyword(s):  
Atomistic Simulation ◽  
Large Scale

Cross Section and Plan View STEM Analysis on Identical Conversion Point of Basal Plane Dislocation to Threading Edge Dislocation of 4H-SiC

2016 ◽  
Vol 858 ◽  
pp. 397-400
Author(s):  
Takahiro Sato ◽  
Yoshihisa Orai ◽  
Toshiyuki Isshiki ◽  
Munetoshi Fukui ◽  
Kuniyasu Nakamura
Keyword(s):  
Cross Section ◽  
Edge Dislocation ◽  
Basal Plane ◽  
Dislocation Line ◽  
Plan View ◽  
Conversion Point ◽  
Partial Dislocations ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Basal Plane Dislocation

Cross section and plan view dislocation analysis at the conversion point of a basal plane dislocation (BPD) into a threading edge dislocation (TED) in a silicon carbide epitaxial wafer was developed using a newly modified multi directional scanning transmission electron microscopy (STEM) technique. Cross section STEM observation in the [-1100] direction, found a conversion point located 5.5 μm from the surface, where two dislocation lines in the basal plane convert into one dislocation line nearly along the hexagonal c axis was observed. Using plan view STEM observation along the [000-1] direction, it is confirmed that the dislocation lines are two partial dislocations of a BPD and one TED by g·b invisibility analysis. This new technique is a powerful tool to evaluate the fundamental dislocation characteristics of power electronics devices.

Atomistic Simulation of the Energy Barrier for Dislocation Movement in Si

2008 ◽  
Vol 33-37 ◽  
pp. 957-962
Author(s):  
S.Y. Kim ◽  
S. Im ◽  
Y.Y. Earmme
Keyword(s):  
Edge Dislocation ◽  
Energy Barrier ◽  
Potential Energy Surfaces ◽  
Structural Changes ◽  
Dislocation Line ◽  
Dislocation Motion ◽  
Layer By Layer ◽  
Dislocation Pair ◽  
Dislocation Movement ◽  
Energy Surfaces

We examine the mobility of an edge dislocation pair on the shuffle plane in Si using action-derived molecular dynamics (ADMD). ADMD is one of the specially designed schemes for finding out the reaction pathways passing through transition states in the landscape of potential energy surfaces. Via ADMD calculations, the various structural changes of dislocation line with atomic resolution and their corresponding energy barriers are evaluated during the dislocation motion. The energy barrier for the movement of an edge dislocation pair on shuffle plane is about 0.24 eV. In this case, one bond between the atoms at the dislocation line is broken first, and then a new bond is formed with the neighboring atom. The movement of the dislocation line is achieved by a sequence of making new bond after bond-breaking of concerned atoms, which occur layer by layer. When the dislocation moves through this mechanism, energy barrier for the dislocation movement does not depend on the length of dislocation line. Thus the present result enables one to surmount the inherent limitation of Peierls-Nabarro’s two-dimensional continuum model, which may fail to describe successfully dislocation motion on the atomistic level.

1A1 Atomistic simulation of the edge dislocation motion in alpha iron under realistic hydrogen concentration conditions

2013 ◽  
Vol 2013 (0) ◽  
pp. 1-2
Author(s):  
Shinya TAKETOMI ◽  
Kazuhiro UCHIDA ◽  
Seiya HAGIHARA
Keyword(s):  
Hydrogen Concentration ◽  
Edge Dislocation ◽  
Atomistic Simulation ◽  
Dislocation Motion ◽  
Alpha Iron

The Atomistic Simulation of Impurity Segregation at the Surfaces of MgO and CaO

1985 ◽  
pp. 397-408 ◽  
Author(s):  
E. A. Colbourn ◽  
W. C. Mackrodt ◽  
P. W. Tasker
Keyword(s):  
Atomistic Simulation ◽  
Impurity Segregation

scholarly journals Direct atomistic simulation of brittle-to-ductile transition in silicon single crystals

2010 ◽  
Vol 1272 ◽  
Author(s):  
Dipanjan Sen ◽  
Alan Cohen ◽  
Aidan P. Thompson ◽  
Adri Van Duin ◽  
William A. Goddard III ◽  
...  
Keyword(s):  
Single Crystals ◽  
Atomistic Simulation ◽  
Large Scale ◽  
Elevated Temperatures ◽  
Experimental Studies ◽  
Crack Tip ◽  
Threshold Value ◽  
Atomic Scale ◽  
Brittle To Ductile Transition ◽  
First Time

AbstractSilicon is an important material not only for semiconductor applications, but also for the development of novel bioinspired and biomimicking materials and structures or drug delivery systems in the context of nanomedicine. For these applications, a thorough understanding of the fracture behavior of the material is critical. In this paper we address this issue by investigating a fundamental issue of the mechanical properties of silicon, its behavior under extreme mechanical loading. Earlier experimental work has shown that at low temperatures, silicon is a brittle material that fractures catastrophically like glass once the applied load exceeds a threshold value. At elevated temperatures, however, the behavior of silicon is ductile. This brittle-to-ductile transition (BDT) has been observed in many experimental studies of single crystals of silicon. However, the mechanisms that lead to this change in behavior remain questionable, and the atomic-scale phenomena are unknown. Here we report for the first time the direct atomistic simulation of the nucleation of dislocations from a crack tip in silicon only due to an increase of the temperature, using large-scale atomistic simulation with the first principles based ReaxFF force field. By raising the temperature in a computational experiment with otherwise identical boundary conditions, we show that the material response changes from brittle cracking to emission of a dislocation at the crack tip, representing evidence for a potential mechanisms of dislocation mediated ductility in silicon.

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