DEFECT DEPENDENCE OF THE DIELECTRIC PERMEABILITY OF QN(TCNQ)2

The conductivity and 9.1 GHz dielectric constant of neutron irradiated Qn(TCNQ)2 single crystals are strongly affected by defect concentrations less than 1 %. This indicates long range electronic coherence of the order of 100 lattice constants in the non-irradiated material for which the coherence length may still be impurity limited. It is suggested that a collective excitation of electrons is responsible for the temperature dependence of the large dielectric constant. © 1979.