Hypothesis of two-dimensional stripe arrangement and its implications for the superconductivity in high-Tc cuprates

Abstract

The hypothesis that holes doped into high-Tc cuprate superconductors organize themselves in two-dimensional (2D) array of diagonal stripes is discussed, and, on the basis of this hypothesis, a new microscopic model of superconductivity is proposed and solved. The model describes two kinds of hole states localized either inside the stripes or in the antiferromagnetic domains between the stripes. The characteristic energy difference between these two kinds of states is identified with the pseudogap. The onset of superconductivity is caused by the interaction, which is assumed to be mediated by the transverse fluctuations of stripes. The superconducting (SC) order parameter predicted by the model has two components, whose quantum phases exhibit a complex dependence on the the center-of-mass coordinate. The model predictions for the tunneling characteristics and for the dependence of the critical temperature (Tc) on the superfluid density show good quantitative agreement with a number of experiments. The model, in particular, predicts that the SC peaks in the tunneling spectra are asymmetric, only when Δ∕Tc>4, where Δ is the SC gap. It is also proposed that, at least in some high-Tc cuprates, there exist two different superconducting states corresponding to the same doping concentration and the same critical temperature. Finally, the checkerboard pattern in the local density of states observed by scanning tunneling microscopy in Bi2Sr2CaCu2O8+δ is interpreted as coming from the states localized around the centers of stripe elements forming the 2D superstructure.

Source-reported materials — not catalogue approval

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