Long-Range Periodicity of S/Au(111) Structures at Low and Intermediate Coverages

P. N. ABUFAGER; G. ZAMPIERI; K. REUTER; M.L. MARTIARENA; H. F. BUSNENGO

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Año: 2014 vol. 118 p. 290 - 297

1932-7447

ABSTRACT: Through a systematic analysis based on DFT calculations, we have studiedthe adsorption of S atoms on Au(111) at low and intermediate coverages (θ ≤ 1/3). Ourcalculations predict ground state structures characterized by two periodicities: (5 × 5) and(√3 × √3)R30°. In line with experiments, the (5 × 5) periodicity seems to dominate in amuch larger coverage range than the (√3 × √3)R30° one, which should be onlyobservable in a narrow coverage window close to 1/3. In addition, our resultsunambiguously reveal the crucial role of S-induced substrate relaxation. Using a first-principles parametrized lattice-gas Hamiltonian approach, we determine lateralinteractions between S atoms which allow us to provide a sound explanation for therelative stability of ground state structures.