Dresden 2011 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

DS: Fachverband Dünne Schichten

DS 33: Progress in Micro- and Nanopatterning: Techniques and Applications II (Focused Session, jointly with O -- Organisers: Graaf, Hartmann)

DS 33.8: Vortrag

Mittwoch, 16. März 2011, 12:45–13:00, GER 38

Dynamics of step bunches on vicinal surfaces: Sublimation, electromigration and transparent steps — •Marian Ivanov¹, Vladislav Popkov², and Joachim Krug¹ — ¹Institut für Theoretische Physik, Universität zu Köln, Köln — ²Dipartimento di Fisica Teorica, Università degli Studi di Salerno, Salerno, 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. We consider a one-dimensional step train evolving in the presence of sublimation, step-step interactions, fast kinetics 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 [3]. This interesting behavior is preserved by adding the corresponding terms due to the effect of electromigration. In the case of fast diffusion we consider a recently introduced model for transparent steps [4] and present simulation results for the evolution of the bunch geometry.

[1] V. Popkov, J. Krug, Europhys. Lett. 72, 1025 (2005) [2] V. Popkov, J. Krug, Phys. Rev. B 73, 235430 (2006) [3] M. Ivanov, V. Popkov, J. Krug, Phys. Rev. E 82, 011606 (2010) [4] B. Ranguelov, S. Stoyanov, Surf. Sci. 603, 2907 (2009)