2009/12/03 by Nicolas Doiron-Leyraud, Pascale Auban-Senzier, Samuel René de Cotret +4
Physics and Astronomy · #cond-mat.supr-con #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.80.214531
published as Phys. Rev. B 80, 214531 (2009) · Accepted for publication in Phys. Rev. B. This paper focuses on a subset of the data presented in arXiv:0905.0964v1
The quasi-1D organic Bechgaard salt (TMTSF)2PF6 displays spin-density-wave (SDW) order and superconductivity in close proximity in the temperature-pressure phase diagram. We have measured its normal-state electrical resistivity ρa(T) as a function of temperature and pressure, in the T → 0 limit. At the critical pressure where SDW order disappears, ρa(T) ∝ T down to the lowest measured temperature (0.1 K). With increasing pressure, ρa(T) acquires a curvature that is well described by ρa(T) = ρ0 + AT + BT2, where the strength of the linear term, measured by the A coefficient, is found to scale with the superconducting transition temperature Tc. This correlation between A and Tc strongly suggests that scattering and pairing in (TMTSF)2PF6 have a common origin, most likely rooted in the antiferromagnetic spin fluctuations associated with SDW order. Analysis of published resistivity data on the iron-pnictide superconductor Ba(Fe1-xCox)2As2 reveals a detailed similarity with (TMTSF)2PF6, suggesting that antiferromagnetic fluctuations play a similar role in the pnictides.