Superconducting and density-wave instabilities of low-dimensional conductors with a Zeeman coupling to a magnetic field

Abstract

In the framework of the weak coupling renormalization group technique we examine the possible instabilities of the extended quasi-one-dimensional electron gas model with both intrachain and interchain electron-electron interactions, including the influence of umklapp scattering and the coupling of spins to a magnetic field. In the limit of purely repulsive intrachain interactions, we confirm the passage from singlet d-wave like superconductivity to an inhomogeneous FFLO state under magnetic field. The passage is accompanied by an anomalous increase of the upper critical field that scales with the antinesting distance from the quantum critical point joining superconductivity to antiferromagnetism in the phase diagram, as well as the strength of interactions. Adding weak repulsive interchain interactions promotes the passage from singlet to triplet f -wave superconductivity which is expanded under field by the development of a triplet FFLO state with zero angular momentum projection for the Cooper pairs. The connection between theory and experiments on the anomalous upper critical field in the Bechgaard salts is discussed.

Quasi one-dimensional organic conductors: from Fröhlich conductivity and Peierls insulating state to magnetically-mediated superconductivity, a retrospective

“…The existence of the high field SC is actually of significant importance for the theory of these superconductors, as it as been ascribed to the signature of the interplay between magnetism and d-wave superconductivity in these Q1D conductors under magnetic field [313,321]. Thermodynamics performed under oriented fields in (TMTSF) 2 ClO 4 is also of great interest in the context of possible FFLO phases.…”

Microscopic theory of the superconducting gap in the quasi-one-dimensional organic conductor (TMTSF)2ClO4 : Model derivation and two-particle self-consistent analysis

“…In strongly 1D system, the odd-frequency pairing state has been suggested [49,71,72]. The magnetic-field effect on the pairing competition has been studied using phenomenological or microscopic approaches [73][74][75][76][77][78][79][80][81][82][83]. Finally, pairing mechanisms that are not mediated by spin or charge fluctuation suggest that anisotropic pairing states may arise [84][85][86].…”