Nodal-line pairing with 1D-3D coupled Fermi surfaces: a model motivated by Cr-based superconductors

Abstract

Motivated by the recent discovery of a new family of Chromium based superconductors, we consider a two-band model, where a band of electrons dispersing only in one direction interacts with a band of electrons dispersing in all three directions. Strong $2k_f$ density fluctuations in the one-dimensional band induces attractive interactions between the three-dimensional electrons, which, in turn makes the system superconducting. Solving the associated Eliashberg equations, we obtain a gap function which is peaked at the "poles" of the three-dimensional Fermi sphere, and decreases towards the "equator". When strong enough local repulsion is included, the gap actually changes sign around the "equator" and nodal rings are formed. These nodal rings manifest themselves in several experimentally observable quantities, some of which resemble unconventional observations in the newly discovered superconductors which motivated this work.

6 pages. 3 figures

References in corpus (6)

• Superconductivity in quasi-one-dimensional K${}_2$Cr${}_3$As${}_3$ with significant electron correlations
• Unconventional superconductivity in quasi-one-dimensional Rb${}_2$Cr${}_3$As${}_3$
• Superconductivity in quasi-one-dimensional Cs2Cr3As3 with large interchain distance
• Anisotropic $H_{c2}$, thermodynamic and transport measurements, and pressure dependence of $T_c$ in K${}_2$Cr${}_3$As${}_3$ single crystals
• Magnetism in Quasi-One-Dimensional A${}_2$Cr${}_3$As${}_3$ (A=K,Rb) superconductors
• Fourier transform of the $2k_F$ Luttinger liquid density correlation function with different spin and charge velocities

Cited by in corpus (3)

• Multiband one-dimensional electronic structure and spectroscopic signature of Tomonoga-Luttinger liquid behavior in K${}_2$Cr${}_3$As${}_3$
• Peculiar properties of Cr${}_3$As${}_3$-chain-based superconductors
• The upper critical field and its anisotropy in RbCr${}_3$As${}_3$