Ab initio Surface Phase Diagram of Sn/Cu (001): Reconciling Experiments with Theory Ab INITIO SURFACE PHASE DIAGRAM of ... LEE et al.

Despite numerous experimental and theoretical studies on the highly miscible Sn/Cu(001) system, a conclusive detailed atomic picture of this rich alloy surface phase diagram is still warranted. Depending of the surface coverage of Sn, a rich variety of Sn/Cu(001) surface structures may be expected, ranging from the so-called phase I to phase IV. An extreme lack of atomic details about them hinders the overall comprehension of this alloy system. We focus on examining the surface energetics and thermodynamics of the Sn/Cu(001) structures to identify the low-energy structures for the experimentally observed phases I-IV. We also discuss the surface electronic structure of these low-energy Sn/Cu(001) structures in terms of their surface work functions and surface dipole moments. Finally, we compare the simulated scanning-tunneling-microscopy (STM) images of these Sn/Cu(001) phases with available experimental STM measurements. We believe this work sets a good theoretical platform for an accurate further investigation of the Sn/Cu bimetallic surface-alloy system for surface-sensitive applications in, e.g., heterogeneous nanocatalysis.