Experimental electronic structure of Be2C

The insulating Be2C thin films have been successfully prepared on a Be surface. A low-energy electron diffraction pattern shows that the films have (100) orientation along the surface normal. We have used angle-resolved photoemission to map out the occupied bulk band dispersion along the T-X direction. The band-gap edges at the X point are 6.7 and 11.5 eV below the valence-band maximum, which is located at the Gamma point. These values are in good agreement with theoretical calculations. The unoccupied bulk electronic structure is measured using C Is near-edge x-ray-absorption spectroscopy. The spectrum is similar in shape to the energy-loss spectrum and the calculated p-partial density of states, while the peak positions are different.