Possibilities of molecular magnetic metals and high T_c superconductors in field effect transistor configurations

Ab initio molecular orbital (MO) and density functional theory (DFT) calculations of neutral and anion radical states of anthracene are performed to elucidate their vibrational frequencies. They are used to calculate the transition temperatures of superconductivity of these species in the field effect transistor (FET) configuration on the basis of the electron-phonon coupling mechanism. Anderson and Kondo lattice models are also examined in relation to possible electronic phases of segregated columns of donors or acceptors with radical groups, and conducting polymers with radical groups in the FET configuration. The effective exchange interactions within conduction electrons and localized spins are calculated by theoretical methods. The electron or hole doping into molecular crystals and/or thin films of these systems in the FET configuration are studied in relation to possible magnetic states, Kondo and dense Kondo states, and superconducting states via spin fluctuations. The cooperative mechanism between the electron-phonon and spin fluctuation is also discussed to search the high T_c superconductor. Finally, the magnetic modifications of helical conducting polymers and DNA chains with chiral spin sources are discussed in relation to possibility of molecular solenoid, which may be generated in the FET configuration.