Paper SS1+AS+HC+NS-TuM10
Progress in Characterizing Submonolayer Island Growth: Capture-Zone Distributions, Growth Exponents, and Transient Mobility
Tuesday, November 8, 2016, 11:00 am, Room 104D
| Session: |
Surface Dynamics, Non-Adiabaticity, and Theory and Modeling of Surface and Interfacial Phenomena |
| Presenter: |
Theodore L. Einstein, University of Maryland, College Park |
| Authors: |
T.L. Einstein, University of Maryland, College Park
A. Pimpinelli, Rice University
J.R. Morales-Cifuentes, Unversity of Maryland, College Park
D.L. González, Universidad del Valle, Colombia
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| Correspondent: |
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Analyzing capture-zone distributions (CZD) using the generalized Wigner distribution (GWD) has proved a powerful way to gain insight into epitaxial growth, in particular to access the critical nucleus size i, as reviewed in [1]. The CZ of an island contains all points closer to that island than to any other and is known as a Voronoi tesselation. This approach complements measurements of the growth exponent α from the scaling (with flux F) of island density N ~ Fα and of the distribution of island sizes. We summarize some extensive Monte Carlo simulations and experiments, especially newer ones, on various systems to which the GWD has been applied. These experiments include atomic or organic adsorbates, sometimes with impurities, and colloidal nano-particles. In some cases, most notably parahexaphenyl (6P) on sputter-modified mica [2], the value i extracted from CZD) differs from the [larger] values of i deduced from N ~ Fα. Furthermore, while the scaling was good, the values of α differed considerably at small and large F, which was attributed to DLA and ALA dynamics [2]. To reconcile the CZD and scaling measurements, we took into account long-known transient mobility (hot precursors) using a rate-equation approach [3]. We also applied this method to data for pentacene (5A) on the same substrate. In applications of the GWD to social phenomena, notably the areas of secondary administrative units (e.g. counties or French arrondissements) [4], lognormal distributions (typically due to multiplicative noise) sometimes arise instead of GWD or gamma distributions; we show this also occurs for some pore-size distributions [5]. *Work at UMD supported by NSF CHE 13-05892
[1] T.L. Einstein, A. Pimpinelli, D.L. González, J. Cryst. Growth 401 (2014) 627; TLE, AP, DLG, J.R. Morales-Cifuentes, J. Physics: Conf. Ser. J. Phys.: Conf. Series 640 (2015) 012024
[2] T. Potocar et al., Phys. Rev. B 83 (2011) 075423 & later work by A. Winkler et al., see [1].
[3] JRM-C, TLE, and AP, Phys. Rev. Lett. 113 (2014) 246101.
[4] R. Sathiyanarayanan, Ph.D. thesis, UMD, 2009; R. Sathiyanarayanan and TLE, preprint.
[5] A.S. DeLoach, B.R. Conrad, TLE, and D.B. Dougherty, submitted.