Quasi-One-Dimensional Organic Metals: Theory and Experiment

Abstract

Given the success of the weak coupling nesting model in explaining thermodynamical properties of the Bechgaard salts at low temperatures and in magnetic fields, we first concentrate on its implications to kinetics in the metallic phase. The model results in nonuniversal temperature dependencies of resistivity and magnetoresistance due to proximity of the metallic and the spin density wave phases, which are in a qualitative agreement with the available experimental data. We then analyze whether the phenomenological nesting model can be justified in frameworks of a more general model of electron-electron interactions in the one-dimensional system improved by three-dimensional effects of the interchain hopping. Properties of the Bechgaard salts look consistent with the Hubbard model with a weak repulsion. Considerable high temperature variation of the magnetic susceptibility is ascribed to localization of electrons by quasi-elastic scattering on thermal phonons. The fact that these materials correspond to the half-filled (hole) band was crucial for the analyses. Except for a new energy scale, introduced by the temperature of a spin density wave transition, no other electronic correlation effects stem from the analysis.