The Cuprate Pseudogap: Competing Order Parameters or Precursor Superconductivity

Abstract

In this paper we compare two broad classes of theories for the pseudogap in cuprate superconductors. The comparison in made in reference to measurements of the superfluid density, ${\rho }_s(T,x)$, in $YB{a}_{2}Cu{O}_{7-\delta }$ films having a wide range of stoichiometries, $\delta$, or, hole doping, $x$. The theoretical challenge raised by these (and previous) data is to understand why the T-dependence of ${\rho }_s(T,x)$ is insensitive to the fermionic excitation gap $\Delta (T,x)$, which opens in the normal state and persists into the superconducting state, when presumably ${\rho }_s(T)$ is governed, at least in part, by fermionic excitations. Indeed, ${\rho }_s(T,x)$ seems to have a BCS-like dependence on $T_c(x)$, which, although not unexpected, is not straightforward to understand in pseudogapped superconductors where $T_c(x)$ and the excitation gap have little in common. Here, we contrast "extrinsic" and "intrinsic" theoretical approaches to the pseudogap and argue that the former (for example, associated with a competing order parameter) exhibits more obvious departures from BCS-like $T$ dependences in ${\rho }_s(T)$ than approaches which associate the pseudogap with the superconductivity itself. Examples of the latter are Fermi liquid based schemes as well as a pair fluctuation mean field theory. Thus far, the measured behavior of the superfluid density appears to argue against an extrinsic interpretation of the pseudogap, and supports instead its intrinsic origin.

9 pages, 8 figures; text rewritten in the PRB format

References in corpus (6)

• The onset of the vortex-like Nernst signal above Tc in La_{2-x}Sr_xCuO_4 and Bi_2Sr_{2-y}La_yCuO_6
• Quasiparticle States around a Nonmagnetic Impurity in D-Density-Wave State of High-$T_c$ Cuprates
• D-wave superconductivity in doped Mott insulators
• Spin and Current Correlation Functions in the \bf d-density Wave State of the Cuprates
• The Superfluid Density in the D-density-wave Scenario
• The Pseudogap Challenge: Understanding the ab-Plane AC Conductivity below Tc

Cited by in corpus (28)

• Superconductivity close to the Mott state: From condensed-matter systems to superfluidity in optical lattices
• Specific temperature dependence of pseudogap in YBa${}_2$Cu${}_3$O${}_{7-\delta }$ nanolayers
• Hydrostatic-pressure effects on the pseudogap in slightly doped YBa2Cu3O7-δ single crystals
• The effect of the pseudogap on suppressing high energy inelastic neutron scattering in superconducting YBa2Cu3O6.5
• Peculiarities in the pseudogap behavior in optimally doped YBa2Cu3O7-δ single crystals under pressure up to 1GPa
• Applying BCS-BEC Crossover Theory To High Temperature Superconductors and Ultracold Atomic Fermi Gases
• A Variational Monte Carlo Study of the Current Carried by a Quasiparticle
• Evidence for decay of spin-waves above the pseudogap in underdoped YBa2Cu3O6.35
• Enhancement of the superconducting transition temperature in cuprate heterostructures
• Fluctuation conductivity and possible pseudogap state in FeAs-based superconductor EuFeAsO(0.85)F(0.15)
• Superfluid Suppression in d-Wave Superconductors due to Disordered Magnetism
• The pseudogap state in superconductors: Extended Hartree approach to time-dependent Ginzburg-Landau Theory
• Feshbach hypothesis of high-Tc superconductivity in cuprates
• London penetration depth in the tight binding approximation: Orthorhombic distortion and oxygen isotope effects in cuprates
• Influence of strong electron irradiation on fluctuation conductivity and pseudogap in YBa${}_2$Cu${}_3$O${}_7$--$\delta$ single crystals
• Tunnel and thermal c-axis transport in BSCCO in the normal and pseudogap state
• Influence of electron irradiation on fluctuation conductivity and pseudogap in $YB{a}_{2}C{u}_3{O}_{7-\delta }$ single crystals
• Features of Excess Conductivity Behavior in a Magnetic Superconductor Dy${}_{0.6}$Y${}_{0.4}$Rh${}_{3.85}$Ru${}_{0.15}$B${}_4$
• Gauge approach to superfluid density in underdoped cuprates
• Unified treatment of Fermi pockets and arcs scenarios for the cuprates: Sum rule consistent response functions of the pseudogap
• Superfluid density in the slave-boson theory
• Fluctuating Cooper pairs in FeSe at temperatures exceeding double Tc
• Effects of annealing on the fluctuation conductivity and pseudogap in slightly doped $HoB{a}_{2}C{u}_3{O}_{7-\delta }$ single crystals
• Nonlinear c-axis transport in Bi_2Sr_2CaCu_2O_(8+d) from two-barrier tunneling
• Superfluid density in cuprates: hints on gauge compositeness of the holes
• Search for Cooper-pair Fluctuations in Severely Underdoped YBCO Films
• Hydrostatic pressure effect on the pseudogap in Y0.77Pr0.23Ba2Cu3O7-δsingle crystals
• Evolution of the pseudogap and excess conductivity of YBa${}_2$Cu${}_3$O${}_{7-\delta }$ single crystals in the course of long-term aging