Pattern Formation in an Oscillatory Medium with Memory Effects: Reversible Roughening in a Surface Reaction

Abstract

Spatiotemporal pattern formation in catalytic CO oxidation on a Pt(110) surface was investigated using low energy electron microscopy to image the laterally varying adsorbate concentrations. It is shown that reversible roughening is part of the pattern-forming process establishing a memory effect in the oscillatory medium. As a result, complex and unusual patterns form under oscillatory conditions. Different types of patterns, each with a characteristic size, coexist such that a hierarchy of length scales is established.