Vacancy Formation and Strain in Low-Temperature<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Cu</mml:mi><mml:mo>/</mml:mo><mml:mi>Cu</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>100</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:math>Growth

Shim, Yunsic; Borovikov, V. A.; Uberuaga, Blas P.; Voter, Arthur F.; Amar, Jacques G.

doi:10.1103/physrevlett.101.116101

Cited by 29 publications

(31 citation statements)

References 18 publications

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“…15͒ thin films grown at temperatures between 110 to 300 K have provided evidence for a surprisingly high vacancy concentration incorporated in deposited thin films. Subsequent molecular-dynamics simulations demonstrated 16 kinetic channels that allow the formation of vacancies or voids in the growing film. Furthermore, low concentration of extremely mobile surface vacancies assist the self-diffusion ͑homoepitaxy͒ of Cu islands on Cu͑001͒ ͑Ref.…”

Section: Introductionmentioning

confidence: 99%

Crucial role of surface in stability and mobility of vacancy clusters in metals

2009

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Ab initio electronic structure calculations are employed to study the stability and mobility of vacancy clusters at or below the Cu͑111͒ surface. The monovacancy formation energy decreases on going from bulk to surface. The strong binding of a nearest-neighbor ͑NN͒ surface divacancy and the negligible binding of a NN divacancy, consisting of a surface and subsurface vacancy, demonstrate the strong ͑weak͒ intraplane ͑inter-plane͒ attractive interaction between vacancies. Similarly, NN surface trivacancies exhibit a wide range of layer-dependent binding behavior. The underlying mechanism is the different elastic contribution ͑atomic relaxation͒ of each layer, giving rise to a preferential two-dimensional clustering of vacancies on the surface. The results reveal a migration mechanism for a NN surface divacancy involving a two-step counterclockwise and clockwise rotation of the center of mass. The migration paths of the NN surface trivacancy include purely translation, rotation, and mixed translation-rotation mechanisms with different energy barriers.

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Section: Introductionmentioning

confidence: 99%

Crucial role of surface in stability and mobility of vacancy clusters in metals

2009

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“…Simulation studies of relatively thin films deposited at grazing angles suggest the development of nanoscale roughness that leads to surface strains. 10 However, a connection between those simulations and the present work is difficult to make because our films were quite thick (100 ML) and they were deposited at near-normal (30 degrees). Future experiments on thinner films and performed as a function of deposition angle are required in order to explore the effect of nanoscale surface roughness effects.…”

Section: Discussionmentioning

confidence: 76%

“…The reentrant roughening was reproduced in KMC simulations by relaxing the funneling condition which introduced internal voids or vacancy clusters, thereby, giving theoretical support for the presence of such incorporated defects 9 . An alternative explanation was later suggested by Shim et al 10 whose accelerated molecular dynamics (MD) simulations reported that large off-normal deposition angles cause nanoscale surface roughness which, in turn, leads to compressive strain comparable in size to that observed in the x-ray reflectivity studies . However, x-ray diffuse scattering experiments by Kim et al, performed for 100 monolayer (ML) Ag(001) homoepitaxial films grown at a considerably smaller off-normal deposition angle, revealed point-defect scattering that provides clear experimental evidence for the existence of large vacancy clusters 11 .…”

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confidence: 92%

X-ray diffuse scattering study of vacancy nanoclusters in homoepitaxial Ag(001) films

2012

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The analysis of x-ray diffuse scattering measurements on Ag homoepitaxial films is presented. The experiments, which establish that a low concentration of large vacancy clusters can be incorporated into noble metals during homoepitaxial growth, were performed on 100 monolayer films of Ag deposited on Ag(001) at low temperature. The diffuse scattering of this film was measured, in situ, near several in-plane Bragg positions in grazing-incidence geometry. Because of the large dilatation from the vacancy clusters, the usual approximations of Huang and Stokes-Wilson scattering cannot be made and it is shown that numerical integration of the diffuse scattering equations leads to good agreement between the data and a point-defect scattering model.

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“…However, the deposition process usually incorporates downward funneling (DF) of atoms deposited at step edges to adsorption sites in lower layers [4,5]. There may also be steering towards any steep sides of multilayer nanoprotrusions [6,7] or shadowing for oblique incidence [8].…”

Section: Introductionmentioning

confidence: 99%

From Initial to Late Stages of Epitaxial Thin Film Growth: STM Analysis and Atomistic or Coarse-Grained Modeling

Evans¹,

Han²,

Ünal³

et al. 2010

AIP Conference Proceedings

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Epitaxial thin film growth by vapor deposition or molecular beam epitaxy under ultra-high vacuum conditions generally occurs in two stages: (i) nucleation and growth of well-separated islands on the substrate; (ii) subsequent formation of a thicker continuous film with possible kinetic roughening. For homoepitaxial growth, two-dimensional (2D) monolayer islands are formed during submonolayer deposition. Typically, the presence of a step-edge barrier inhibits downward transport and leads to the formation of mounds (multilayer stacks of 2D islands) during multilayer growth. For heteroepitaxial growth, islands formed in the initial stages of deposition sometimes have a 2D monolayer structure. However, they may instead exhibit bilayer or 3D multilayer structure due to, e.g., a high film surface energy, strain, or quantum size effects. Various growth modes are possible for thicker films. Atomistic modeling provides the most detailed picture of film growth. For coherent (defect-free) epitaxial films, lattice-gas modeling analyzed by kinetic Monte Carlo simulation (KMC) is particularly successful in describing film growth on the appropriate time and length scales. For large islands or complex systems, another effective and instructive approach is laterally coarse-grained step-dynamics modelingwhich tracks only the evolution of step edges in each layer. However, fully coarse-grained 3D continuum modeling for the evolution of a film height function does not yet have predictive capability. Examples are provided for: Ag homoepitaxy on (100), (111) and (110) Abstract. Epitaxial thin film growth by vapor deposition or molecular beam epitaxy under ultra-high vacuum conditions generally occurs in two stages: (i) nucleation and growth of well-separated islands on the substrate; (ii) subsequent formation of a thicker continuous film with possible kinetic roughening. For homoepitaxial growth, two-dimensional (2D) monolayer islands are formed during submonolayer deposition. Typically, the presence of a step-edge barrier inhibits downward transport and leads to the formation of mounds (multilayer stacks of 2D islands) during multilayer growth. For heteroepitaxial growth, islands formed in the initial stages of deposition sometimes have a 2D monolayer structure. However, they may instead exhibit bilayer or 3D multilayer structure due to, e.g., a high film surface energy, strain, or quantum size effects. Various growth modes are possible for thicker films. Atomistic modeling provides the most detailed picture of film growth. For coherent (defect-free) epitaxial films, lattice-gas modeling analyzed by kinetic Monte Carlo simulation (KMC) is particularly successful in describing film growth on the appropriate time and length scales. For large islands or complex systems, another effective and instructive approach is laterally coarse-grained step-dynamics modeling which tracks only the evolution of step edges in each layer. However, fully coarse-grained 3D continuum modeling for the evolution of a film height function does not ...

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Vacancy Formation and Strain in Low-TemperatureCu/Cu(100)Growth

Cited by 29 publications

References 18 publications

Crucial role of surface in stability and mobility of vacancy clusters in metals

Crucial role of surface in stability and mobility of vacancy clusters in metals

X-ray diffuse scattering study of vacancy nanoclusters in homoepitaxial Ag(001) films

From Initial to Late Stages of Epitaxial Thin Film Growth: STM Analysis and Atomistic or Coarse-Grained Modeling

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