Effect of interface dislocation Burgers vectors on elastic fields in anisotropic bicrystals

Vattré, A.; Demkowicz, Michael J.

doi:10.1016/j.commatsci.2014.02.044

Cited by 20 publications

(13 citation statements)

References 33 publications

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“…We calculate interface stress fields using an efficient, semi-analytical method developed previously 22 31 32 . This method accounts for the elastic anisotropy of solids A and B as well as for differences in elastic constants between them.…”

Section: Resultsmentioning

confidence: 99%

“…It generates elastic field solutions consistent with a pre-specified interface crystallographic character (that is, misorientation and interface plane orientation 33 ) and with vanishing far-field stresses. The method has been successfully applied to a variety of homo- and hetero-phase interfaces 22 31 32 and has been validated through comparisons with atomistic simulations 18 .…”

Section: Resultsmentioning

confidence: 99%

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Non-random walk diffusion enhances the sink strength of semicoherent interfaces

et al. 2016

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Clean, safe and economical nuclear energy requires new materials capable of withstanding severe radiation damage. One strategy of imparting radiation resistance to solids is to incorporate into them a high density of solid-phase interfaces capable of absorbing and annihilating radiation-induced defects. Here we show that elastic interactions between point defects and semicoherent interfaces lead to a marked enhancement in interface sink strength. Our conclusions stem from simulations that integrate first principles, object kinetic Monte Carlo and anisotropic elasticity calculations. Surprisingly, the enhancement in sink strength is not due primarily to increased thermodynamic driving forces, but rather to reduced defect migration barriers, which induce a preferential drift of defects towards interfaces. The sink strength enhancement is highly sensitive to the detailed character of interfacial stresses, suggesting that ‘super-sink' interfaces may be designed by optimizing interface stress fields. Such interfaces may be used to create materials with unprecedented resistance to radiation-induced damage.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Non-random walk diffusion enhances the sink strength of semicoherent interfaces

et al. 2016

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“…As a result, ambiguity arises whether the Burgers vector should be defined by the film or the substrate lattice constant. It has been suggested that an appropriate Burgers vector would enable far field stresses to become zero [12,13]. However, the far field stresses are obviously not zero in the continuous films except when a precise number of misfit dislocations are formed to cancel exactly the misfit strain.…”

Section: Introductionmentioning

confidence: 99%

An atomistically validated continuum model for strain relaxation and misfit dislocation formation

Zhou

Ward

Zimmerman

et al. 2016

Journal of the Mechanics and Physics of Solids

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In this paper, molecular dynamics (MD) calculations have been used to examine the physics behind continuum models of misfit dislocation formation and to assess the limitations and consequences of approximations made within these models. Without compromising the physics of misfit dislocations below a surface, our MD calculations consider arrays of dislocation dipoles constituting a mirror imaged "surface". This allows use of periodic boundary conditions to create © 2016. This manuscript version is made available under the Elsevier user license http://www.elsevier.com/open-access/userlicense/1.0/ 2 a direct correspondence between atomistic and continuum representations of dislocations, which would be difficult to achieve with free surfaces. Additionally, by using long-time averages of system properties, we have essentially reduced the errors of atomistic simulations of large systems to "zero". This enables us to deterministically compare atomistic and continuum calculations. Our work results in a robust approach that uses atomistic simulation to accurately calculate dislocation core radius and energy without the continuum boundary conditions typically assumed in the past, and the novel insight that continuum misfit dislocation models can be inaccurate when incorrect definitions of dislocation spacing and Burgers vector in latticemismatched systems are used. We show that when these insights are properly incorporated into the continuum model, the resulting energy density expression of the lattice-mismatched systems is essentially indistinguishable from the MD results.

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“…We only show in this letter that the dislocation force varies by charge significantly which can perturb the polarization charge in nitride heterostructures and the stress/electric fields in piezoelectric- based electronic devices. Any further predictions of dislocation motion require dynamic analysis of ensembles of dislocations with discrete Burgers vector or continuous distribution of disregistry 31 using discrete/continuum models and field theories 32 as well as utilizing the dislocation density-based model to account for the dislocation interactions. 33 The presented analytical method characterizes the piezoelectric polarization in a bilayer system while emphasizes on the importance of charge and its effect on the dislocation force.…”

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confidence: 99%

Near-interface charged dislocations in AlGaN/GaN bilayer heterostructures

Sangghaleh

Pan

Han

2014

Applied Physics Letters

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Understanding the behavior of semiconductor dislocation defects in AlGaN/GaN heterostructures is necessary in order to produce powerful and efficient transistors. This letter presents a straightforward technique to characterize dislocation defects with charges along their loops in a bilayer system. This is important regarding the behavior of near-interface dislocations in order to obtain an insight of the mechanical and physical responses. We characterize piezoelectric polarization and emphasize on the importance of dislocation-core electric charge. The results elaborate the variations of the dislocation force by the accumulation of charge and provide an explanation for the dominant dislocation types in nitride semiconductors.

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Effect of interface dislocation Burgers vectors on elastic fields in anisotropic bicrystals

Cited by 20 publications

References 33 publications

Non-random walk diffusion enhances the sink strength of semicoherent interfaces

Non-random walk diffusion enhances the sink strength of semicoherent interfaces

An atomistically validated continuum model for strain relaxation and misfit dislocation formation

Near-interface charged dislocations in AlGaN/GaN bilayer heterostructures

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