ANGLE-RESOLVED PHOTOEMISSION-STUDY OF NBC(111) SURFACE

Angle-resolved photoemission spectroscopy utilizing synchrotron radiation (25 ≤ hv ≤ 90 eV) has been used to study the electronic structure of NbC0.9(111) surface. Assuming a free-electron like final state band, bulk dispersion curves along Γ-L direction are mapped. Polarization dependent measurements are performed to decide the initial state symmetry of each band. With regard to the energy levels and symmetries, the experimental band generally corresponds to the theoretical band structure. The surface induced states are identified by an oxygen adsorption study. The dispersion relation of this state is mapped in a surface Brillouin zone, and it is found that the state is a half-filled metallic state. © 1990 Pergamon Press plc.