Hamburg 2001 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 5: Fachsymposium 1: Unkonventionelle Supraleitung

TT 5.12: Vortrag

Montag, 26. März 2001, 18:00–18:15, A

From spin-Peierls to superconductivity: (TMTTF)₂PF₆ under high pressure — •Heribert Wilhelm¹, Didier Jaccard², Denis Jérome³, and Joel Moser³ — ¹Max-Planck-Institut Chemische Physik fester Stoffe, Noethnitzerstr. 40, 01187 Dresden — ²Dep. Physique de la Matière Condensée, Université de Genève, Quai E.-Ansermet 24, CH-1211 Genève — ³Laboratoire de Physique des Solides, Université de Paris-Sud, F-91405 Orsay

The transport properties of the organic conductor (TMTTF)₂PF₆ have been studied under pressure up to 8.3 GPa in the temperature range 30 mK<T<300 K. A metallic ground state is stabilized above 4.7 GPa. At this pressure the drop in resistivity at T_c=2.2 K is assigned to the stabilization of a superconducting state which is suppressed by a magnetic field op 0.8 Tesla. Superconductivity is not longer observed above 50 mK beyond 7 GPa. (TMTTF)₂PF₆ is the first member of the (TM)₂X series to exhibit a spin-Peierls ground state at ambient pressure and superconductivity under high pressure. The vicinity of an antiferromagnetic to the superconducting state and the presence of critical antiferromagnetic fluctuations above T_c strongly support the intriguing possibility that the interchain exchange of antiferromagnetic fluctuations may provide the attractive interaction which is requested to form Cooper-pairs.