Theory of Quasi-One-Dimensional Organic Conductors

University Of Maryland, College Park, College Park MD

Investigators

Abstract

This research is devoted to the theory of quasi-one-dimensional (Q1D) organic conductors (TMTSF)2X and (TMTTF)2X, where TMTSF is tetramethyltetraselenafulvalene, TMTTF is tetramethyltetrathiafulvalene, and X represents a monovalent inorganic anion, such as PF6 and ClO4. These materials demonstrate an antonishingly rich variety of physical properties and states: metallic, insulating, superconductive, charge-and spin-density-wave states, antiferromagnetism, spin-Peierls states, and the state of Mott-Hubbard paramagnetic insulator. They exhibit a multitude of magnetic oscillations as a function of the magnitude and orientation of the magnetic field. A strong magnetic field induces the cascade of phase transitions between the magnetic-field-induced spin-density waves (FISDW), which exhibit the quantum Hall effect. Theoretical research will be conducted on the following topics: fractional quantum Hall numbers of the subgap electron states; electron states in superconducting junctions; bound electron states at the superconducting and FISDW vortices and impurities; collective modes in the triplet superconducting state; and, coesistence of metallic Fermi surface and charge gap. There will be close collaboration with experiments and an emphasis on real materials. %%% Theoretical research will be conducted on a novel class of organic conducting materials which display a rich variety of properties. These materials are of great fundamental interest due these properties arising in organic materials and of great practical interest due to many potential applications. ***