Angle-Resolved Photoemission Study of the Clean and Oxygen Covered ZrC(111) Surface

Abstract

Angle-resolved photoemission spectroscopy utilizing synchrotron radiation has been used to study the electronic structure of a ZrC(111) clean surface and the surface covered with oxygen. The spectra of the clean surface show a sharp peak at just below the Fermi level, and the peak is ascribed to the emission from a surface state formed through a charge redistribution around the surface. The polarization dependent measurements show that the surface state is derived from the 4d z 2 orbital of the surface Zr atom at the Γ̄ point. Oxygen adsorbs dissociatively forming a (1×1) overlayer at the saturation coverage. As the surface is covered with oxygen, the peak from the surface state is quenched and O 2p z and 2p x , y induced bonding states are formed at 5.3 and 6.0 eV, respectively, at the Γ̄ point. The two-dimensional band structure of the O 2p induced states suggests that the O 2p x ,2p y and 2p z states should have nearly the same contribution to the chemisorption bonding on the ZrC(111) surface.