Low-coverage heteroepitaxial growth with interfacial mixing

• Main Authors: Mazzitello, K. I, Delgado, L. M, Iguain, J. L
• Format: Journal Article
• Language: English
• Published: 26-05-2015
• Subjects: Physics - Mesoscale and Nanoscale Physics; Physics - Statistical Mechanics
• DOI: 10.48550/arxiv.1407.7807

J. Stat. Mech. (2015) P01015 We investigate the influence of intermixing on heteroepitaxial growth
dynamics, using a two-dimensional point island model, expected to be a good
approximation in the early stages of epitaxy. In this model, which we explore
both analytically and numerically, every deposited B atom diffuses on the
surface with diffusion constant $D_{\rm B}$, and can exchange with any A atom
of the substrate at constant rate. There is no exchange back, and emerging
atoms diffuse on the surface with diffusion constant $D_{\rm A}$. When any two
diffusing atoms meet, they nucleate a point island. The islands neither diffuse
nor break, and grow by capturing other diffusing atoms. The model leads to an
island density governed by the diffusion of one of the species at low
temperature, and by the diffusion of the other at high temperature. We show
that these limit behaviors, as well as intermediate ones, all belong to the
same universality class, described by a scaling law. We also show that the
island-size distribution is self-similarly described by a dynamic scaling law
in the limits where only one diffusion constant is relevant to the dynamics,
and that this law is affected when both $D_{\rm A}$ and $D_{\rm B}$ play a
role.