Quasi-one-dimensional conductors

Abstract

This review is intended to be an introduction to the physics of quasi-one-dimensional conductors which exhibit a Peirels instability. It is first shown that the Peirels instability occurs because of a fundamental instability in the electronic system. The mean field theory of the Peierls instability for the Fröhlich Hamiltonian of a one-dimensional electronic system which interacts with lattice modes of vibration is then discussed. The properties of the periodic lattice distortions and the accompanying charge density waves which result from the instability are described and the important effects of fluctuations and three dimensionality are considered. The observed properties of the mixed valence planar transition metal compound, K 2[Pt(CN) 4]Br 0.30·3H 2O, and the organic charge transfer salt, tetrathiofulvalinium tetracyanoquinodimethane, are then presented and they are interpreted in terms of the Peierls-Fröhlich model of one-dimensional conductor. Theoretical predictions for one-dimensional electronic systems in, which Coulomb interactions are important are also described and their relevance to tetrathiofulvalinium tetracyanoquinodimethane is considered.