Surface electronic structure of HfC(1 1 1)

Angle-resolved photoemission spectroscopy utilizing synchrotron radiation has been used to study the electronic structure of an HfC(1 1 1) surface. A sharp peak is observed at just below the Fermi level in normal-emission spectra. The peak is assigned as the emission from a surface state from the analyses of the photon energy dependence of the spectra and a crude test using oxygen adsorption. Resonant photoemission study shows that the state is mostly composed of the 5d orbitals of the surface Hf atoms. The two-dimensional band structure of the state is measured in the Γ M and Γ K directions, and the state is found to disperse in a narrow energy region around the Fermi level.