The metallic transport of (TMTSF)_2X organic conductors close to the superconducting phase

Pascale Auban-Senzier (1) , Denis Jérome (1) , Nicolas Doiron-Leyraud (2) , Samuel René de Cotret (2) , Abdel Sedeki (2) , Claude Bourbonnais (2) , Louis Taillefer (2) , P. Alemany (3) , Enric Canadell (4) , Klaus Bechgaard (5)

1 LPS - Laboratoire de Physique des Solides
2 Département de Physique et RQMP
3 IQTCUB - Departament de Quimica Fisica and Institut de Quimica Teorica i Computacional
4 ICMAB - Institut de Ciència de Materials de Barcelona
5 Department of Chemistry, H.C. Oersted Institute

Comparing resistivity data of quasi-one dimensional superconductors (TMTSF)_2PF_6 and (TMTSF)_2ClO_4 along the least conducting c*-axis and along the high conductivity a -axis as a function of temperature and pressure, a low temperature regime is observed in which a unique scattering time governs transport along both directions of these anisotropic conductors. However, the pressure dependence of the anisotropy implies a large pressure dependence of the interlayer coupling. This is in agreement with the results of first-principles DFT calculations implying methyl group hyperconjugation in the TMTSF molecule. In this low temperature regime, both materials exhibit for rc a temperature dependence aT + bT^2. Taking into account the strong pressure dependence of the anisotropy, the T-linear rc is found to correlate with the suppression of the superconducting Tc, in close analogy with ra data. This work is revealing the domain of existence of the 3D coherent regime in the generic (TMTSF)_2X phase diagram and provides further support for the correlation between T-linear resistivity and superconductivity in non-conventional superconductors.

Domaines: Electrons fortement corrélés [cond-mat.str-el]

Pascale Auban-Senzier, Denis Jérome, Nicolas Doiron-Leyraud, Samuel René de Cotret, Abdel Sedeki, et al.. The metallic transport of (TMTSF)_2X organic conductors close to the superconducting phase. Journal of Physics: Condensed Matter, 2011, 23, pp.345702. ⟨10.1088/0953-8984/23/34/345702⟩. ⟨hal-00592154v2⟩