Identification of the monolayer oxygen structure on by means of directional elastic peak electron spectroscopy (DEPES)

The investigation of 1 monolayer of oxygen on the Ru ( 1 0 1 ¯ 0 ) surface by directional elastic peak electron spectroscopy (DEPES) reveals high sensitivity of this surface method to light gases. The presentation of the experimental data as the anisotropy DEPES pattern shows an angular orientation of the oxygen adsorbate with respect to the substrate atoms. The straightforward identification of the oxygen structure is supported by a quantitative analysis providing oxygen atom coordinates within the unit cell. Highlights ► Mono-atomic O layer on Ru is detected by elastic scatterings of primary electrons. ► Experimental result straightforwardly reveals O adatom position within unit cell. ► Presented method substantially extends application of the retarding field analyzer.