k-dependent SU(4) model of high-temperature superconductivity and its coherent-state solutions

TL;DR

This paper introduces an extended SU(4)k model for high-temperature superconductivity that incorporates explicit momentum dependence, providing insights into pseudogap phenomena, Fermi arcs, and the coexistence of antiferromagnetism and superconductivity.

Contribution

The paper develops and solves a momentum-dependent SU(4)k model, extending previous SU(4) models to better match experimental observations like ARPES data.

Findings

Quantitative description of pseudogap temperature scale.

Explanation for larger T* along anti-nodal directions.

Prediction of doping-dependent momentum windows with suppressed antiferromagnetism.

Abstract

We extend the SU(4) model [1-5] for high-Tc superconductivity to an SU(4)k model that permits explicit momentum (k) dependence in predicted observables. We derive and solve gap equations that depend on k, temperature, and doping from the SU(4)k coherent states, and show that the new SU(4)k model reduces to the original SU(4) model for observables that do not depend explicitly on momentum. The results of the SU(4)k model are relevant for experiments such as ARPES that detect explicitly k-dependent properties. The present SU(4)k model describes quantitatively the pseudogap temperature scale and may explain why the ARPES-measured T* along the anti-nodal direction is larger than other measurements that do not resolve momentum. It also provides an immediate microscopic explanation for Fermi arcs observed in the pseudogap region. In addition, the model leads to a prediction that even in the underdoped regime, there exist doping-dependent windows around nodal points in the k-space, where antiferromagnetism may be completely suppressed for all doping fractions, permitting pure superconducting states to exist.