We report the results of photoemission spectroscopy on the potassium concentration (x) dependence of Kx picene films on graphite. The results show a systematic shift of a whole valence band and the appearance of a clear Fermi edge for a certain value of x, with additional structures at higher binding energies. Observed spectral evolutions are reminiscent to those of doped C60, implying that the Kx picene film has multiple phases depending on the K concentration. Appearance of a clear Fermi edge, in contrast to multilayer Kx picene films on Au, SiO2, and Ag(111) substrates, where no clear Fermi edges are observed, suggests that the emergence of the metallic states for Kx picene films depends on the specific molecular orientations in the films on different substrates.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2013 Dec 11|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics