Dresden 2009 – wissenschaftliches Programm
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SYSO: Symposium Self-organizing Surfaces and Interfaces
SYSO 6: Self-Organizing Surfaces and Interfaces V
SYSO 6.2: Vortrag
Donnerstag, 26. März 2009, 14:15–14:30, GÖR 226
Anti-coarsening and complex dynamics of step bunches on vicinal surfaces — •Marian Ivanov1, Vladislav Popkov2, and Joachim Krug1 — 1Institut für Theoretische Physik, Universität zu Köln, Zülpicher Str.77, 50937 Köln, Germany — 2Dipartimento di Fisica Teorica "E. R. Caianiello", Universita degli Studi di Salerno, Via Ponte Don Melillo, 84084 Fisciano (SA), Italy
Using morphological instabilities one can produce templates for nanoscale technology. One example of such an instability is step bunching, which splits a regular vicinal surface into regions of low and high density of monoatomic steps. The dynamics of the surface is described by the Burton-Cabrera-Frank model with boundary conditions provided by mass conservation at the steps. We consider a one-dimensional step train evolving in the presence of sublimation, electromigration, step-step interactions and an Ehrlich-Schwoebel effect. We show that the interplay of sublimation and step-step interactions removes the conservation law for the crystal volume in the co-moving frame, which has been assumed in previous work [1,2]. As a consequence large step bunches are found to break up into smaller bunches of a characteristic size, and the monotonic coarsening dynamics of the volume-conserving model is replaced by a complex quasiperiodic pattern. A preliminary dynamic phase diagram summarizing the different behaviors as a function of the model parameters will be presented.
[1] V. Popkov, J. Krug, Europhys. Lett. 72, 1025 (2005), [2] V. Popkov, J. Krug, Phys. Rev. B 73, 235430 (2006)