First-principles study of oxygen adsorption on Fe(1Â 1Â 0) surface

► We model three O adsorption superstructures on Fe(1 1 0) surface. ► The atomic geometry and electronic properties have been calculated. ► Oxygen adsorption induces the surface spin density to be positive at Fermi level, unlike the clean Fe(1 1 0) surface. ► The surface Fe-O magnetic interaction causes the adsorbate O spin splitting. ► The adsorbate O exchange splitting band calculations need improve.