Possibilities of molecular magnetic metals and high T-c superconductors infield effect transistor configurations

Ab initio molecular orbital (MO) and density functional theory (DFT) calcul ations of neutral and anion radical states of anthracene are performed to e lucidate their vibrational frequencies. They are used to calculate the tran sition temperatures of superconductivity of these species in the field effe ct transistor (FET) configuration on the basis of the electron-phonon coupl ing mechanism. Anderson and Kondo lattice models are also examined in relat ion to possible electronic phases of segregated columns of donors or accept ors with radical groups, and conducting polymers with radical groups in the FET configuration. The effective exchange interactions within conduction e lectrons and localized spins are calculated by theoretical methods. The ele ctron or hole doping into molecular crystals and/or thin films of these sys tems in the FET configuration are studied in relation to possible magnetic states, Kondo and dense Kondo states, and superconducting states via spin f luctuations. The cooperative mechanism between the electron-phonon and spin fluctuation is also discussed to search the high Tc superconductor. Finall y, the magnetic modifications of helical conducting polymers and DNA chains with chiral spin sources are discussed in relation to possibility of molec ular solenoid, which may be generated in the FET configuration. (C) 2001 Jo hn Wiley & Sons, Inc.