Oxygen-induced nano-faceting of Re(<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si32.gif" overflow="scroll"><mml:mn>11</mml:mn><mml:mover accent="true"><mml:mn>2</mml:mn><mml:mo stretchy="true">¯</mml:mo></mml:mover><mml:mn>1</mml:mn></mml:math>)

Wang, Hao; Chen, Wenhua; Bartynski, Robert

doi:10.1016/j.susc.2014.12.015

Cited by 3 publications

(1 citation statement)

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“…Let us mention another type of surface for which the interfacial phase separation operates. Indeed, an initially stable surface may facet as oxygen exposure modifies the surface energy anisotropy [70,71]. This process is known as adsorbate-induced faceting and can be used as nanotemplates, for instance, to synthesize metallic nanoparticles [72].…”

Section: Faceting Instabilitymentioning

confidence: 99%

Regularized anisotropic motion-by-curvature in phase-field theory: Interface phase separation of crystal surfaces

2022

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The kinetic equation for anisotropic motion-by curvature is ill-posed when the surface energy is strongly anisotropic. In this case, corners or edges are present on the Wulff shape, which span a range of missing orientations. In the sharp-interface problem the surface energy is augmented with a curvature-dependent term that rounds the corners and regularizes the dynamic equations. This introduces a new length scale in the problem, the corner size. In phase-field theory, a diffuse description of the interface is adopted. In this context, an approximation of the Willmore energy can be added to the phase-field energy so as to regularize the model. In this paper, we discuss the convergence of the Allen-Cahn version of the regularized phase-field model toward the sharp-interface theory for strongly anisotropic motion-by-curvature, in three dimensions. Corners at equilibrium are also compared to theory for different corner sizes. Then, we investigate the dynamics of the faceting instability, when initially unstable surfaces decompose into stable facets. For crystal surfaces with trigonal symmetry, we find the following scaling law L ∼ t 1/3 , for the growth in time t of a characteristic morphological length scale L, and coarsening is found to proceed by either edge contraction or cube removal, as in the sharp-interface problem. Finally, we study nucleation of crystal surfaces in a two-phase system, as for a terrace-and-step surface. We find that, as compared with saddle point nucleation, ridge crossing is dynamically favoured. However, the induced nucleation mechanism, when a facet induces at its wake formation of additional facets, is not evidenced with a type-A dynamics.

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Section: Faceting Instabilitymentioning

confidence: 99%