Theory of coupled dual dynamics of macroscopic phase coherence and microscopic electronic fluids: Effect of dephasing on cuprate superconductivity

Abstract

By using the gauge-invariant kinetic equation approach [Yang and Wu, Phys. Rev. B 98, 094507 (2018); Phys. Rev. B 100, 104513 (2019)], we construct the coupled dual dynamics of macroscopic phase coherence and microscopic electronic fluids in cuprate superconductors. We prove that the developed dual dynamics provides an efficient and simplified approach to formulate the dephasing process of macroscopic superconducting phase coherence, as well as its influence on microscopic electronic fluids (including gap, densities of superfluid and normal fluid, and in particular, the transport property to determine superconducting transition temperature Tc). We then present a theoretical description of the preformed Cooper pairs in a pseudogap state. The key origin of a pseudogap state comes from the quantum effect of disorder, which excites the macroscopic inhomogeneous phase fluctuation through the Josephson effect. Influenced by this phase fluctuation, there exist normal fluid and viscous superfluid below Tc in cuprate superconductors, in addition to conventional nonviscous superfluid. The normal fluid always emerges around nodal points even at zero temperature, whereas the viscous superfluid emerges due to the friction between superfluid and normal fluids. Particularly, the nonviscous superfluid gets suppressed when the phase fluctuation is enhanced by the increasing temperature, until vanishes at Tc. Then, the system enters the pseudogap state, showing the nonzero resistivity as well as the finite gap from the viscous superfluid. By further increasing temperature to Tos, the viscous superfluid and hence gap vanish. An experimental scheme to distinguish the densities of normal fluid as well as viscous and nonviscous superfluids is proposed. Finally, this theory is also applied to low-dimensional disordered s-wave superconductors.

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