Angle-resolved photoemission study of the surface state on NbC(111)

Abstract

Angle-resolved photoemission spectroscopy utilizing synchrotron radiation has been used to study the surface electronic structure of a NbC0.9(111) single crystal. A strong emission from a surface state is observed just below the Fermi level (EF) which is rapidly quenched by hydrogen adsorption. The dispersion relation of this state is mapped in a surface Brillouin zone along the ΓM and ΓK directions. It is found that the surface state disperses upwards and crosses the Fermi level for both ΓM and ΓK dir dispersion and symmetry of this state are in good agreement with theoretical results for the surface state on TiC(111). The photon energy dependence of the cross section of the surface state is also investigated and some resonance effects are found.