Gossamer Superconductivity, New Paradigm?

TL;DR

This paper reviews the concept of gossamer superconductivity, proposing it as a unifying framework to understand various phenomena in high-Tc cuprates, CeCoIn$_{5}$, and organic superconductors, emphasizing the role of d-wave density waves.

Contribution

It introduces the idea that gossamer superconductivity, involving coexisting d-wave density waves, explains experimental observations and phase diagrams in multiple unconventional superconductors.

Findings

d-wave density waves explain Nernst effect and magnetoresistance

Phase diagram modeled with two order parameters, dDW and superconductivity

Spatially periodic dDW state analogous to FFLO becomes stable in overdoped regime

Abstract

We shall review our recent works on d-wave density wave (dDW) and gossamer superconductivity (i.e. d-wave superconductivity in the presence of dDW) in high-T$_{c}$ cuprates and CeCoIn$_{5}$. a) We show that both the giant Nernst effect and the angle dependent magnetoresistance (ADMR) in the pseudogap phases of the cuprates and CeCoIn$_{5}$ are manifestations of dDW. b) The phase diagram of high-T$_{c}$ cuprates is understood in terms of mean field theory, which includes two order parameters $\Delta_{1}$ and $\Delta_{2}$, where one order parameter is from dDW and the other from d-wave superconductivity. c) In the optimally to the overdoped region we find the spatially periodic dDW, an analogue of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, becomes more stable. d) In the underdoped region where $\Delta_{2}/\Delta_{1} \ll 1$ the Uemera relation is obtained within the present model. We speculate that the gossamer superconductivity is at the heart of high-T$_{c}$ cuprate superconductors, the heavy-fermion superconductor CeCoIn$_{5}$ and the organic superconductors $\kappa$- (ET)$_{2}$Cu(NCS)$_{2}$ and (TMTSF)$_2$PF$_{6}$.