Regensburg 2010 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 40: Topical Session Growth Kinetics I
MM 40.1: Topical Talk
Mittwoch, 24. März 2010, 16:00–16:30, H4
Modeling the Role of Co-deposited Impurities in Growth: What Causes the Distinctive Step Meandering and Pyramidal Mounds on Cu(001)* — •Theodore L. Einstein1, Rajesh Sathiyanarayanan1,2, Ajmi BH. Hamouda1,3, and Alberto Pimpinelli1,4 — 1U. Maryland, College Park, USA — 2Now at Pennsylvania State U., USA — 3U. Monastir, Tunisia — 4UBP-Clermont II, France, & Science Attaché, French Consulate, Houston, TX USA
Several attempts—not involving impurities—failed to account for all the distinctive features of the growth instabilities observed on Cu vicinal surfaces;1 recent kinetic Monte Carlo studies showed that codeposition of impurities during growth could do so.2 To identify the responsible impurity, we compute3 nearest-neighbor binding energies (ENN) and terrace diffusion barriers (Ed) for several impurity atoms on Cu(001) using VASP. Codeposition (with Cu) of mid-transition elements (Fe, Mn, W) could cause the observed instabilities; W is most likely. Based on ENN and Ed, we classify the impurities into four sets.3 Each set produces qualitatively different surface morphologies in both the step-flow and the submonolayer (θ ≤ 0.7 ML) regimes. In the latter, we find the variations with θ of the number of islands and their mean size, as well as their critical nucleus size from the distribution of capture-zone areas (via fits to the generalized Wigner distribution4).
*Support: NSF MRSEC #DMR 05-20471; computing at NCSA, UIUC
1N.Néel, T.Maroutian, L.Douillard, H.-J.Ernst, JPCM 15 (’03) S3227
2A. Hamouda et al., PRB 77 (2008) 245430; JPCM 21 (2009) 084215
3RS, Ph.D. thesis, UMD, 2009 4AP & TLE, PRL 99 (2007) 226102