Nature of Stripes in the Generalized t-J Model Applied to The Cuprate Superconductors

TL;DR

This paper investigates the energetics and stability of stripe-ordered superconducting states in cuprates using a generalized t-J model and renormalized mean field theory, revealing close energy competition among states and the influence of crystal anisotropy.

Contribution

It provides a detailed theoretical analysis of stripe and superconducting phase coexistence in cuprates, highlighting the energetic proximity of various modulated states and the role of crystal anisotropy.

Findings

Stripe antiphase SC states have energies close to the ground state but are slightly higher.

Anisotropy in the crystal structure favors stripe resonating valence bond states.

Additional physical effects may be needed for the stability of stripe SC states.

Abstract

Recent transport properties on the stripe phase in La$_{\text{1.875}}$Ba$_{\text{01.25}}$CuO$_{\text{4}}$ by Li \textit{et al.} found 2-dimensional superconductivity over a wide temperature range including a Berezinski-Kosterlitz-Thouless transition at a temperature T=16K, with 3-dimensional superconducting (SC) ordering only at T=4K. These results contradict the long standing belief that the onset of superconductivity is suppressed by stripe ordering and suggest coexistence of stripe and SC phases. The lack of 3-D superconducting order above T=4K requires an antiphase ordering in the SC state to suppress the interlayer Josephson coupling as proposed by Berg \textit{et al.}. Here we use a renormalized mean field theory for a generalized t-J model to examine in detail the energetics of the spin and charge stripe ordered SC states including possible antiphase domains in the SC order. We find that the energies of these modulated states are very close to each other and that the anisotropy present in the low temperature tetragonal crystal structure favors stripe resonating valence bond states. The stripe antiphase SC states are found to have energies very close,but always above, the ground state energy which suggests additional physical effects are responsible for their stability.