Investigation of the surface phase diagram of Fe(1 1 0)–S

Reconstructions and overlayer structures of the Fe(1 1 0) surface at different sulfur (S) coverage are presented by atomically resolved scanning tunneling microscopy combined with Auger electron spectroscopy and low energy electron diffraction investigations. S overlayers were obtained by annealing a Fe(1 1 0) single crystal to 700 °C in order to induce S segregation from the bulk. Fe(1 1 0)c(6×4), (3×1) and (1×1) reconstructions were found at sub or monolayer S coverage. At S coverage above one monolayer a (2×1) super structure was formed on top of the Fe(1 1 0)(1×1)–S structure. When increasing the coverage further, S grow in a zigzag formation from step edges across the terraces. These zigzag rows grow in the [1 1̄ 1] and [0 0 1] directions and form a quasi-ordered parallelogram structure.