The structure and surface chemistry of ultrathin metallic films of one metal on another are strongly influenced by factors such as lattice mismatch and the formation of near-surface alloys. New morphologies may result with modified chemical properties which in turn open up different routes for molecular adsorption, desorption and surface functionalization, with important consequences in several fields of application.The Cu/Au(111) system has received the attention of many studies, only a few however have been performed in ultra-high vacuum (UHV), using surface sensitive techniques. In this contribution, the room temperature deposition of copper onto the (22× √ 3)-Au(111) surface, from submonolayer to thick film, is investigated using scanning tunnelling microscopy (STM).The onset of copper adsorption is seen to occur preferentially at alternate herringbone elbows, with a preference for hcp sites. With increasing coverage, copper-rich islands exhibit a reconstructed surface reminiscent of the clean Au(111) herringbone reconstruction. Disordered, pseudo-ordered and ordered surface layers are observed upon annealing. Models for the initial adsorption/incorporation mechanism, formation of adlayers and evolution with increasing coverage and annealing are qualitatively discussed. Further, the reactivity of copper-doped Au (111) systems is considered towards the adsorption of organic molecules of interest in nanotechnology and in catalytic applications.

Geometrical structure and electronic characteristics of ultrathin metallic films of one metal on another are strongly influenced by factors such as lattice mismatch and formation of nearsurface alloys. Doped systems often show modified chemical-physical properties which may be amenable to different reactivity routes. Copper-gold surface alloys have received the attention of several studies, only a few of which have been undertaken in an UHV environment, using surface sensitive techniques. In this contribution, systems produced upon room temperature deposition of copper on the (22×√3)-Au(111) surface, at various copper loadings and annealed to different temperatures, are investigated using scanning tunnelling microscopy and synchrotron radiation based techniques (X-ray photoelectron diffraction, photoemission), with comparison with some theoretical modelling. Overall the fcc lattice is essentially maintained on preparation. Upon thermal treatments structural and compositional changes, in favour of alloyed structures with tetragonal packing, are seen.

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The electricity system of Great Britain is becoming increasingly decentralised, with more complex patterns of power production, transportation and consumption. New types of ‘flexibility’ are being developed to facilitate and manage these changes. This POSTnote reviews ways of developing flexibility, as well as technical and economic barriers to doing so.