Surface energy bands observed in photoemission from a (1 × 1)-N structure on Cr (100)

The surface structure obtained on Cr (100) by diffusion of nitrogen from the bulk is studied by angle resolved photoemission. It is found that nitrogen is bonded in an ordered (1 × 1) configuration with a crystallographic point group C_4v. The data display a strongly dispersive two dimensional Bloch character for the N2p derived resonances. For these bands the symmetry at the $\text{Γ}$ point and the dispersion along the $\text{Δ}$ and $\text{Σ}$ lines of the surface Brillouin zone are determined. The results indicate a strong interaction of the nitrogen atoms with the substrate and favor the intersticial fourfold hollow position.