Surface electronic structure of α-Mo2C(0 0 0 1)

The electronic structure of α-Mo2C(0 0 0 1) has been investigated by angle-resolved photoemission spectroscopy utilizing synchrotron radiation. A sharp peak is observed at 3.3 eV in normal-emission spectra. Since the peak shows no dispersion as a function of photon energy and is sensitively attenuated by oxygen adsorption, the initial state of the peak is attributed to a surface state. Resonant photoemission study shows that the state includes substantial contribution of 4d orbitals of the Mo atoms in the second layer. The emissions with constant kinetic energies of 22 and 31 eV above the Fermi level (EF) are found in normal-emission spectra, and these emissions are interpreted as originating from the Mo N1N23V and N23VV Auger transitions, respectively.