This review attempts to present the most salient developments of research on organic conductors and superconductors during the past 10 years. A theoretical introduction treats instabilities of quasi-one-dimensional electron systems and associated precursor effects which are relevant to the experimental results on organic conductors. We then describe the characterization of quasi-one-dimensional organic conductors by their transport, optical and magnetic properties. Finally, two sections are devoted to the experimental investigation of the low temperature instabilities: lattice instability in TTF-TCNQ and related compounds, superconducting or antiferromagnetic instabilities in the (TMTSF) 2 X series. The importance of one-dimensional fluctuations is emphasized in both lattice and superconducting instabilities.

Organic conductors and superconductors

Superconductivity, that is, the possibility for electrons to flow through a conductor without any energy loss, has been the fuel for a very large number of industrial applications of physics in the twentieth century. Just to mention some of them which are important in current life, we have the power loss energy transfer, the production of very strong magnetic fields for medical imaging or for plasma confinement (the fusion problem) voltage standards, particle accelerators, and magnetic flux sensors.

Organic conductors: from charge density wave TTF-TCNQ to superconducting (TMTSF)2PF6.

Rational design of synthetic metal superconductors

The author reviews several important aspects of the problem of one-dimensional metals, including a discussion of their instability, a survey of various materials which are more or less nearly one-dimensional, a fairly detailed treatment of the elementary excitations of charge density waves and a discussion of their electromagnetic properties.

https://iopscience.iop.org/article/10.1088/0034-4885/42/7/004/pdf

One-dimensional metals and charge density wave effects in these materials

The stability of restricted Hartree–Fock solutions and the implied spin and/or space broken symmetry Hartree–Fock solutions are studied using ab initio models of finite chains of hydrogen atoms with Born–Karman boundary conditions and nondegenerate ground state. We also examined the basis set effects, the role of the nuclear framework distortion as related to the bond‐length alternation problem in cyclic polyenes and the higher order instabilities for a large range of internuclear separations. The possible physical implications of the symmetry breaking in the independent particle model are discussed and studied in a considerable detail for the smallest cycle considered, containing six hydrogen atoms. An excellent agreement with the existing infinite chain results is also pointed out. Finally, the relationship with the stability problem and broken symmetry solutions for cyclic polyene models and the sources of these instabilities are examined and discussed as well as their implications for the character an...

Stability of Hartree–Fock solutions and symmetry breaking in the independent particle model: Ab initio case study of the LCAO–MO–SCF solutions for finite chains of hydrogen atoms

F. Gautier

Papers

Physical properties of highly anisotropic systems: radical-ion salts and charge transfer complexes