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Related papers: Classification of step bunching phenomena

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We study the continuum epitaxial model for elastic interacting atomic steps on vicinal surfaces proposed by Xiang and E (Xiang, SIAM J. Appl. Math. 63:241-258, 2002; Xiang and E, Phys. Rev. B 69:035409, 2004). The non-local term and the…

Analysis of PDEs · Mathematics 2022-04-22 Tao Luo , Yang Xiang , Nung Kwan Yip

The Burton-Cabrera-Frank (BCF) model for the flow of line defects (steps) on crystal surfaces has offered useful insights into nanostructure evolution. This model has rested on phenomenological grounds. Our goal is to show via scaling…

Mesoscale and Nanoscale Physics · Physics 2015-06-22 Jianfeng Lu , Jian-Guo Liu , Dionisios Margetis

We study the continuum limit in 2+1 dimensions of nanoscale anisotropic diffusion processes on crystal surfaces relaxing to become flat below roughening. Our main result is a continuum law for the surface flux in terms of a new…

Materials Science · Physics 2009-11-13 John Quah , Dionisios Margetis

We study a recently proposed nonlinear evolution equation describing the collective step meander on a vicinal surface subject to the Bales-Zangwill growth instability [O. Pierre-Louis et al., Phys. Rev. Lett. (80), 4221 (1998)]. A careful…

Materials Science · Physics 2009-10-31 J. Kallunki , J. Krug

Arising as a fluctuation phenomenon, the equilibrium distribution of meandering steps with mean separation $<\ell>$ on a "tilted" surface can be fruitfully analyzed using results from RMT. The set of step configurations in 2D can be mapped…

Statistical Mechanics · Physics 2009-11-10 T. L. Einstein

The probability distribution p(l) of an atom to return to a step at distance l from the detachment site, with a random walk in between, is exactly enumerated. In particular, we study the dependence of p(l) on step roughness, presence of…

Condensed Matter · Physics 2011-01-12 M. Bisani , W. Selke

The growth of crystal surfaces, under non-equilibrium conditions, involves the displacement of mono-atomic steps by atom diffusion and atom incorporations into steps. The time-evolution of the growing crystal surface is thus governed by a…

Materials Science · Physics 2009-11-11 Thomas Frisch , Alberto Verga

We investigate the nonlinear evolution of the Bales-Zangwill instability, responsible for the meandering of atomic steps on a growing vicinal surface. We develop an asymptotic method to derive, in the continuous limit, an evolution equation…

Materials Science · Physics 2014-06-17 Alberto Verga

A continuum theory is used to predict scaling laws for the morphological relaxation of crystal surfaces in two independent space dimensions. The goal is to unify previously disconnected experimental observations of decaying surface…

Materials Science · Physics 2009-11-13 Dionisios Margetis

Steps with spacings of microns form on top of mesas fabricated on Si(111) that is annealed at temperatures where sublimation becomes important. Upon annealing, mesas first develop ridges along their edges, effectively creating craters which…

Materials Science · Physics 2009-11-10 Kee-Chul Chang , Jack M. Blakely

Burton-Cabrera-Frank (BCF) theory has proven to be a versatile framework to relate surface morphology and dynamics during crystal growth to the underlying mechanisms of adatom diffusion and attachment at steps. For an important class of…

The point defect thermodynamics in a general family of binary compounds, including B2 compounds as a specific representative, are classified by way of two non-trivial energy parameters. The scheme is applied to published ab initio defect…

Materials Science · Physics 2015-03-13 Michael Leitner

Most existing analyses of (stochastic) gradient descent rely on the condition that for $L$-smooth costs, the step size is less than $2/L$. However, many works have observed that in machine learning applications step sizes often do not…

Optimization and Control · Mathematics 2022-06-10 Kwangjun Ahn , Jingzhao Zhang , Suvrit Sra

We show that a scaling approach successfully characterizes clustering and intermittency in space and time, in systems of noninteracting particles driven by fluctuating surfaces. We study both the steady state and the approach to it, for…

Soft Condensed Matter · Physics 2019-01-15 Tapas Singha , Mustansir Barma

A discrete version of deposition-diffusion equations appropriate for description of step flow on a vicinal surface is analyzed for a two-dimensional grid of adsorption sites representing the stepped surface and explicitly incorporating…

Mesoscale and Nanoscale Physics · Physics 2016-04-11 R. Zhao , J. W. Evans , T. J. Oliveira

We study the step meandering instability on a surface characterized by the alternation of terraces with different properties, as in the case of Si(001). The interplay between diffusion anisotropy and step stiffness induces a finite…

Statistical Mechanics · Physics 2009-11-11 Thomas Frisch , Alberto Verga

We consider a Branching Random Walk on $\R$ whose step size decreases by a fixed factor, $0<b<1$, with each turn. This process generates a random probability measure on $\R$, that is, the limit of uniform distribution among the $2^n$…

Probability · Mathematics 2011-07-20 Itai Benjamini , Ori Gurel-Gurevich , Boris Solomyak

It is shown that step moving to meet solution flow can be unstable against lateral perturbations. The instability of long-wavelength perturbations occurs at values of the solution flow intensity less than some critical value depending on…

Condensed Matter · Physics 2009-10-28 Serge Yu. Potapenko

Human mobility clustering is an important problem for understanding human mobility behaviors (e.g., work and school commutes). Existing methods typically contain two steps: choosing or learning a mobility representation and applying a…

Machine Learning · Computer Science 2023-01-23 Haoji Hu , Haowen Lin , Yao-Yi Chiang

The phase-ordering kinetics of a bulk uniaxial nematic liquid crystal is addressed using techniques that have been successfully applied to describe ordering in the O(n) model. The method involves constructing an appropriate mapping between…

Condensed Matter · Physics 2009-10-30 Robert A. Wickham