Accessing surface Brillouin zone and band structure of picene single crystals

We have experimentally revealed the band structure and the surface Brillouin zone of insulating picene single crystals (SCs), the mother organic system for a recently discovered aromatic superconductor, with ultraviolet photoelectron spectroscopy (UPS) and low-energy electron diffraction with laser for photoconduction. A hole effective mass of 2.24 m_0 and the hole mobility mu_h >= 9.0 cm^2/Vs (298 K) were deduced in Gamma-Y direction. We have further shown that some picene SCs did not show charging during UPS even without the laser, which indicates that pristine UPS works for high-quality organic SCs.