Equilibrium structures and properties of Au-Pd surfaces and nanoclusters

What is it about?

An extensive study of the ordered structures of Au-Pd alloys in the bulk and near to flat and nanocluster surfaces is reported. The Metropolis Monte Carlo sampling of the equilibrium configurations in the so-called "semi-grand canonical" ensemble is applied, which allows to find stable ordered structures in the whole range of compositions. Order/disorder transitions of selected structures are additionally studied.

Featured Image

Why is it important?

Three ordered bulk phases are predicted at low temperature, centred around Pd compositions of 25%, 50%, and 75%. Some predicted order-disorder transition temperatures are significantly lower compared to the bulk phase diagram, but in good agreement with ab initio results in literature. Surface enrichment in Au and partial subsurface enrichment in Pd is systematically predicted. A new formula of the short-range order parameter, suitable for bulk and nanoparticles is used and proved effective.