Superconducting pairing and density-wave instabilities in quasi-one-dimensional conductors

J. C. Nickel; R. Duprat; C. Bourbonnais; N. Dupuis

doi:10.1103/PhysRevB.73.165126

paper

Superconducting pairing and density-wave instabilities in quasi-one-dimensional conductors

arXiv:cond-mat/0510744 · doi:10.1103/PhysRevB.73.165126

Abstract

Using a renormalization group approach, we determine the phase diagram of an extended quasi-one-dimensional electron gas model that includes interchain hopping, nesting deviations and both intrachain and interchain repulsive interactions. d-wave superconductivity, which dominates over the spin-density-wave (SDW) phase at large nesting deviations, becomes unstable to the benefit of a triplet $f$ -wave phase for a weak repulsive interchain backscattering term $g_{1}^{⊥} > 0$ , despite the persistence of dominant SDW correlations in the normal state. Antiferromagnetism becomes unstable against the formation of a charge-density-wave state when $g_{1}^{⊥}$ exceeds some critical value. While these features persist when both Umklapp processes and interchain forward scattering ( $g_{2}^{⊥}$ ) are taken into account, the effect of $g_{2}^{⊥}$ alone is found to frustrate nearest-neighbor interchain $d$ - and $f$ -wave pairing and instead favor next-nearest-neighbor interchain singlet or triplet pairing. We argue that the close proximity of SDW and charge-density-wave phases, singlet d-wave and triplet $f$ -wave superconducting phases in the theoretical phase diagram provides a possible explanation for recent puzzling experimental findings in the Bechgaard salts, including the coexistence of SDW and charge-density-wave phases and the possibility of a triplet pairing in the superconducting phase.

19 pages, 13 figures

Superconducting pairing and density-wave instabilities in quasi-one-dimensional conductors

Abstract

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