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MM: Fachverband Metall- und Materialphysik

MM 26: Poster Session

MM 26.71: Poster

Dienstag, 23. März 2010, 14:45–16:30, Poster C

Anti-coarsening and complex dynamics of step bunches on vicinal surfaces during sublimation — •Marian Ivanov¹, Vladislav Popkov², and Joachim Krug¹ — ¹Institut für Theoretische Physik, Universität zu Köln, Zülpicher Str.77, D-50937 Köln — ²Interdisziplinäres Zentrum für Komplexe Systeme, Rheinische Friedrich-Wilhelms-Universität Bonn, Römerstraße 164, D-53117 Bonn

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, 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.

[1] V. Popkov, J. Krug, Europhys. Lett. 72, 1025 (2005) [2] V. Popkov, J. Krug, Phys. Rev. B 73, 235430 (2006)