Dominant role of the surface in photoemission from quasi-one dimensional conductors: K0.3MoO3

The electronic structure of the quasi-one dimensional oxide conductor K0.3MoO3 has been studied using both X-ray photoelectron spectroscopy (XPS) and angle resolved photoemission (ARP) spectroscopy. We find that the spectra are dominated by surface effects, particularly deviations from stoichiometry. We report changes in the line shape and binding energy of the Mo 3d core level XPS spectra that are due to variations in core hole screening related to the density of defects in the surface layer. We also discuss the role of surface defects in modifying ARP spectra close to the Fermi level, particularly in the context of recent claims to observe Luttinger liquid behavior in photoemission spectra from K0.3MoO3.