Theory of fluctuation superconductivity from electron-phonon interactions in pseudo-one-dimensional systems

Abstract

The physics of quasi-one-dimensional solids which undergo a Peierls distortion, such as the organic material TTF-TCNQ (tetrathiofulvalinium-tetracyanoquinodimethan) is discussed. In particular, the effect of fluctuations into the Fr\"ohlich superconducting state on the free energy and the electrical conductivity is examined theoretically at temperatures above that of the Peierls distortion. A phenomenological approach is used, but the physical basis for a microscopic treatment is given and the results are compared with the effect of fluctuations into a BCS superconducting state. It is found that such fluctuations give a paraconductivity which is too small to account for the extraordinary conductivity peaks reported for TTF-TCNQ.