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

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

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2014 vol. 118 p. 290 - 297

1932-7447

Through a systematic analysis based on DFT calculations, we have studied the adsorption of S atoms on Au(111) at low and intermediate coverages (θ ≤ 1/3). Our calculations predict ground state structures characterized by two periodicities: (5×5) and (√3x√3)R30º. In line with experiments, the (5×5) periodicity seems to dominate in a much larger coverage range than the (√3x√3)R30º one, which should be only observable in a narrow coverage window close to 1/3. In addition, our results unambiguously reveal the crucial role of S-induced substrate relaxation. Using a first-principles parameterized lattice-gas Hamiltonian approach, we determine lateral interactions between S atoms which allow us to provide a sound explanation for the relative stability of ground state structures.