Correlation between linear resistivity and Tc in the Bechgaard salts and the pnictide superconductor Ba(Fe1−xCox)2As2

Abstract

The quasi-one-dimensional 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.

Source-reported materials — not catalogue approval

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