Superconductivity was recently discovered in solid potassium-intercalated picene (K322ph), in which the picene molecule becomes trianionic (22ph3-). In this Letter, we conduct a theory-based study of the superconductivity of 22ph3- within the framework of BCS theory. We estimate the density of states N(εF) on the Fermi level to be 2.2 states per (eVmoleculespin) by using the theoretical intramolecular electron-phonon coupling lx and the experimental superconducting transition temperature Tc of 18 K. The theoretical value is consistent with the 1.2 states per (eVmoleculespin) determined experimentally for K322ph with Tc=18K, indicating the validity of our theoretical treatment and the electron-phonon mechanism for superconductivity. The predicted lx, 0.206 eV, for 22ph3- is larger than any value reported for organic superconductors, so picene may have the largest lx among the superconductors reported so far.
ASJC Scopus subject areas
- Physics and Astronomy(all)