Complete miscibility between different crystallographic structures Monte Carlo simulations of Cu-Ag deposited on Cu(001)

Abstract : Monte Carlo simulations of an Ag$_c$Cu$_{1-c}$ monolayer deposited onto Cu(001) show that a complete solubility of two elements adopting different crystallographic structures can be observed in the surface, while experimental bulk phase diagrams preclude a similar phenomenon in the bulk. While the deposited pure Ag monolayer is pseudo-hexagonal and the pure Cu monolayer is square and pseudomorphic, for intermediate concentrations a disordered state appears in which square and hexagonal environments, respectively due to Cu and Ag coexist. As a result, the surface phase diagram does not present any miscibility gap at 650 K.