Impurity controlled Superconductivity/Spin Density Wave interplay in the organic superconductor : (TMTSF)_2ClO_4

Nada Joo (1, 2) , Pascale Auban-Senzier (1) , Claude R. Pasquier (1) , Denis Jérome (1) , Klaus Bechgaard (3)

1 LPS - Laboratoire de Physique des Solides
2 LPMC - Laboratoire de Physique de la matière Condensée [Tunis]
3 H. C. Oersted Institute

The study of the anion ordered (TMTSF)_2ClO_4_(1-x)ReO_4_x, solid solution in the limit of a low ReO_4- substitution level (0<=x<=17%) has revealed a new and interesting phase diagram. Superconductivity is drastically suppressed as the effect of ReO_4- non magnetic point defects increases following the digamma behaviour for usual superconductors in the presence of paramagnetic impurities. Then, no long range order can be stabilized above 0.1K in a narrow window of substitution. Finally, an insulating SDW ground state in ReO_4- -rich samples is rapidly stabilized with the decrease of the potential strength leading to the doubling of the transverse periodicity. This extensive study has shown that the superconducting order parameter must change its sign over the Fermi surface.

Mots clés: Transition ordre désordre; Supraconductivité organique; Impuretés non magnétiques

Domaines: Supraconductivité [cond-mat.supr-con]; Electrons fortement corrélés [cond-mat.str-el]

Nada Joo, Pascale Auban-Senzier, Claude R. Pasquier, Denis Jérome, Klaus Bechgaard. Impurity controlled Superconductivity/Spin Density Wave interplay in the organic superconductor : (TMTSF)_2ClO_4. EPL - Europhysics Letters, 2005, 72 (4), pp.645-651. ⟨10.1209/epl/i2005-10281-1⟩. ⟨hal-00007713⟩