SU(2) approach to the pseudogap phase of high-temperature superconductors: electronic spectral functions

TL;DR

This paper employs an SU(2) mean-field theory combined with variational wavefunctions to analyze the electronic spectral functions in the pseudogap phase of cuprates, revealing asymmetric gap structures and their evolution.

Contribution

It introduces a novel SU(2) approach to model the pseudogap phase, connecting fluctuations between superconducting and staggered-flux states with spectral features.

Findings

Spectral functions show asymmetric gaps interpolating between superconducting and staggered-flux states.

Gap asymmetry changes sign at the Fermi surface crossing the diagonal.

Model predicts spectral features consistent with experimental photoemission data.

Abstract

We use an SU(2) mean-field theory approach with input from variational wavefunctions of the t-J model to study the electronic spectra in the pseudogap phase of cuprates. In our model, the high-temperature state of underdoped cuprates is realized by classical fluctuations of the order parameter between the d-wave superconductor and the staggered-flux state. Spectral functions of the intermediate and the averaged states are computed and analyzed. Our model predicts a photoemission spectrum with an asymmetric gap structure interpolating between the superconducting gap centered at the Fermi energy and the asymmetric staggered-flux gap. This asymmetry of the gap changes sign at the point where the Fermi surface crosses the diagonal (\pi,0)-(0,\pi).