Princeton/Exxon Experimental Studies of Organic Charge Transfer Salts

点击翻译按钮获取中文摘要

The field associated with organic charge transfer salts has virtually exploded within the past several years. From a single material which was superconducting at - 1K under pressure, there are now several families of compounds with Tc's up to 12K at ambient pressure. In addition, these are beautiful model systems for studying a wealth of new physical phenomena which result from a combination of reduced dimensionality, relatively small bandwidths and strong electron-electron interactions. They have been most active in the past grant period in the investigations of the remarkable properties of these materials in high magnetic fields. The (TMTSF)2X compounds show a unique cascade of magnetic field induced spin density wave transitions involving aspects of the integer and fractional Quantum Hall Effect, commensurability of the SDW wavelength with the magnetic length and the underlying lattice, Landau bands and subbands, and new types of quantum oscillations. Although there has been rapid theoretical development in this area, some of the more recent experiments and new theories suggest that there are still more interesting phenomena to be observed. They therefore propose a further study of the magnetic field effects using different compounds and additional probes. They also plan a series of experiments on the new organic superconductors to elucidate the nature of the superconductivity, and the roles played by correlations, dimensionality and disorder. A vital part of this work is the synthesis of high quality single crystals. Our past research was only made possible by the synthetic effort at Exxon under the direction of Dr. L.Y. Chaing. This effort will continue and be expanded to develop and characterize new materials as well as prepare established ones.