ORGANIC CONDUCTORS - FERMI-SURFACE AND SPECIFIC-HEAT STUDIES

We briefly review some of the recent high-field de Haas-van Alphen (dH vA) results we obtained for the quasi-two-dimensional organic metals a nd superconductors of the type alpha-(ET)(2)X, where ET (=BEDT-TTF) is bis(ethylenedithio)-tetrathiafulvalene and X is a monovalent anion. W e further report on new dHvA, Shubnikov-de Haas, and specific-heat res ults for the recently synthesized organic superconductor beta''-(ET)(2 )SF5CH3CF2SO3 (T-c = 4.5 K). The Fermi-surface topology, the possible influence of the low dimensionality on the quantum oscillations, and t he influence of many-body interactions are discussed. The results indi cate the importance of electron-phonon interaction and point towards s trong coupling. (C) 1998 Elsevier Science B.V. All rights reserved.