Computer simulations of two-dimensional Sn-Cu alloys on (100) and (111) Cu surfaces

We have performed calculations of Sn deposition on Cu(111) and Cu(100) surfaces. The atomic interactions are described by modified embedded atom method (MEAM) potentials. This is a modification of the embedded atom method (EAM) to include higher moments in the electron density. We find the at low coverages Sn deposited on Cu(111) leads to the formation of a two-dimensional (2D) alloy phase with a p (√3 × √3)-R 30° structure which is stable up to temperatures of 900K. These results are in agreement with ion-scattering experiments of thin films of Sn on Cu(111). For deposition of Sn on Cu(100), a 0.25 monolayer (ML) coverage results in the formation of a stable 2D alloy phase with a p(2 × 2) structure. This result is also in agreement with LEED measurements.