Eur. Phys. J. B 21, 175-183 (2001)
https://doi.org/10.1007/PL00011120

The case for universality of the phase diagram of the Fabre and Bechgaard salts

¹ Département de Physique de la Matière Condensée, Université de Genève, Quai Ernest-Ansermet 24, 1211 Geneva 4, Switzerland
² Centre de Recherche sur les Propriétés Électroniques de Matériaux Avancés, Département de Physique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
³ Laboratoire de Physique des Solides (associé au CNRS) , bâtiment 510, Université de Paris-Sud, 91405 Orsay, France
⁴ Laboratoire Hétérochimie des Matériaux Organiques ENSCM/ESA-5076, 34296 Montpellier Cedex 5, France

Corresponding author: ^a wilhelm@cpfs.mpg.de

Received: 10 January 2001
Published online: 15 May 2001

Abstract

We report the observation of superconductivity in the spin-Peierls Fabre salt (TMTTF)₂PF₆ from pressure dependent electrical transport measurements above a threshold of 4.35 GPa. The data complete the sequence of ground states of this compound in the temperature and pressure plane adducing an empirical basis to the universal character of the phase diagram of the Fabre salts and their selenide analogues, the Bechgaard salts. The structure of the phase diagram at the approach of the crossover between spin-density wave and superconducting states is compared with the results of scaling theory of the interplay between both electronic instabilities under pressure. The comparison supports the view that magnetism and superconductivity in these compounds have a common electronic origin.