Refined BCF-type boundary conditions for mesoscale surface step dynamics
Abstract
Deposition on a vicinal surface with alternating rough and smooth steps is described by a solid-on-solid model with anisotropic interactions. Kinetic Monte Carlo (KMC) simulations of the model reveal step pairing in the absence of any additional step attachment barriers. We explore the description of this behavior within an analytic Burton-Cabrera-Frank (BCF)-type step dynamics treatment. Without attachment barriers, conventional kinetic coefficients for the rough and smooth steps are identical, as are the predicted step velocities for a vicinal surface with equal terrace widths. However, we determine refined kinetic coefficients from a two-dimensional discrete deposition-diffusion equation formalism which accounts for step structure. These coefficients are generally higher for rough steps than for smooth steps, reflecting a higher propensity for capture of diffusing terrace adatoms due to a higher kink density. Such refined coefficients also depend on the local environment of the step and can even become negative (corresponding to net detachment despite an excess adatom density) for a smooth step in close proximity to a rough step. Incorporation of these refined kinetic coefficients into a BCF-type step dynamics treatment recovers quantitatively the mesoscale step-pairing behavior observed in the KMC simulations.
- Authors:
-
- Iowa State Univ., Ames, IA (United States)
- Publication Date:
- Research Org.:
- Ames Laboratory (AMES), Ames, IA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- OSTI Identifier:
- 1234521
- Alternate Identifier(s):
- OSTI ID: 1198513
- Report Number(s):
- IS-J-8642
Journal ID: ISSN 1098-0121; PRBMDO
- Grant/Contract Number:
- AC02-07CH11358
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Physical Review. B, Condensed Matter and Materials Physics
- Additional Journal Information:
- Journal Volume: 91; Journal Issue: 23; Journal ID: ISSN 1098-0121
- Publisher:
- American Physical Society (APS)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 97 MATHEMATICS AND COMPUTING
Citation Formats
Zhao, Renjie, Ackerman, David M., and Evans, James W. Refined BCF-type boundary conditions for mesoscale surface step dynamics. United States: N. p., 2015.
Web. doi:10.1103/PhysRevB.91.235441.
Zhao, Renjie, Ackerman, David M., & Evans, James W. Refined BCF-type boundary conditions for mesoscale surface step dynamics. United States. https://doi.org/10.1103/PhysRevB.91.235441
Zhao, Renjie, Ackerman, David M., and Evans, James W. Wed .
"Refined BCF-type boundary conditions for mesoscale surface step dynamics". United States. https://doi.org/10.1103/PhysRevB.91.235441. https://www.osti.gov/servlets/purl/1234521.
@article{osti_1234521,
title = {Refined BCF-type boundary conditions for mesoscale surface step dynamics},
author = {Zhao, Renjie and Ackerman, David M. and Evans, James W.},
abstractNote = {Deposition on a vicinal surface with alternating rough and smooth steps is described by a solid-on-solid model with anisotropic interactions. Kinetic Monte Carlo (KMC) simulations of the model reveal step pairing in the absence of any additional step attachment barriers. We explore the description of this behavior within an analytic Burton-Cabrera-Frank (BCF)-type step dynamics treatment. Without attachment barriers, conventional kinetic coefficients for the rough and smooth steps are identical, as are the predicted step velocities for a vicinal surface with equal terrace widths. However, we determine refined kinetic coefficients from a two-dimensional discrete deposition-diffusion equation formalism which accounts for step structure. These coefficients are generally higher for rough steps than for smooth steps, reflecting a higher propensity for capture of diffusing terrace adatoms due to a higher kink density. Such refined coefficients also depend on the local environment of the step and can even become negative (corresponding to net detachment despite an excess adatom density) for a smooth step in close proximity to a rough step. Incorporation of these refined kinetic coefficients into a BCF-type step dynamics treatment recovers quantitatively the mesoscale step-pairing behavior observed in the KMC simulations.},
doi = {10.1103/PhysRevB.91.235441},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 23,
volume = 91,
place = {United States},
year = {Wed Jun 24 00:00:00 EDT 2015},
month = {Wed Jun 24 00:00:00 EDT 2015}
}
Web of Science