Stripes, pseudogaps, and SO(6) in the cuprate superconductors

TL;DR

This paper explores the theoretical framework of SO(6) symmetry to describe instabilities in cuprate superconductors and uses slave boson calculations to link stripe phases with doping levels.

Contribution

It introduces an SO(6) symmetry model for high-T_c cuprate instabilities and connects stripe phases with doping-dependent superspin groundstates.

Findings

SO(6) describes nesting and pairing instabilities

Stripe phases are stabilized by electron-phonon coupling

Doping influences the crossover between superspin states

Abstract

We briefly summarize two related calculations. First, we demonstrate that the instabilities (either nesting or pairing) associated with the high-T_c cuprates can be described by an SO(6) transformation group. There are two independent 6-dimensional representations (`superspins'). One superspin combines Zhang's 5-component superspin with a flux phase instability; the other involves a charge density wave, s-wave superconductivity, and an exotic spin current. The second calculation is a self-consistent slave boson calculation, which provides a good description of the doping dependence of the photoemission dispersion in terms of dynamic striped phases. The stripes are stabilized by strong electron-phonon coupling, and provide evidence for a doping-dependent crossover between the two superspin groundstates.