Oxygen adsorption on a ZrC(111) surface: angle-resolved photoemission study

Angle-resolved photoemission spectroscopy utilizing synchrotron radiation has been used to study the adsorption state of oxygen on a ZrC(111) surface. Oxygen adsorbs dissociatively at room temperature forming a (3×3)R30° overlayer at 0.4–0.8 L and a (1×1) overlayer for further exposure. The two-dimensional band structure of the O 2p-derived states is measured for the (1×1)-O surface in the two symmetry directions; 〈21̄1̄〉 (Γ̄M̄) and 〈011̄〉 (Γ̄K̄) directions of the ZrC(111) surface. It is found that the O 2px, 2py and 2pz-derived bands are formed at nearly the same binding energy region, indicating that the O 2px, 2py and 2pz orbitals should have an almost equal contribution to the chemisorption bonding on the ZrC(111) surface.