title: Phase transition driven discontinuity in thermodynamic size selection.
abstract: We show how an order-disorder phase transition in a two-dimensional system can discontinuously alter the shape and size of stress-stabilized self-assembled nanostructures. Low energy electron microscopy was used to study the dealloying of the Cu(111)-sqrt[3]×sqrt[3]-R30°-Bi surface alloy. The gradual expulsion of embedded bismuth from the alloy with increasing temperature induces a hard-hexagon-type order-disorder transition in the surface alloy. Our low energy electron microscopy results demonstrate how the loss of long-range order induces enormous changes in the domain patterns that the alloy forms with a Bi overlayer phase. We propose that the occurrence of phase transitions in one of the two surface phases that constitute a self-assembled domain pattern, provides a general, largely unexplored, mechanism that can be used to influence the morphological details of two-dimensional nanostructures.
authors.affiliation: Physics of Interfaces and Nanomaterials, MESA Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: van Gastel
authors.forename: D
authors.initials: D
authors.lastname: Kaminski
authors.forename: E
authors.initials: E
authors.lastname: Vlieg
authors.forename: B
authors.initials: B
authors.lastname: Poelsema