Unified treatment of Fermi pockets and arcs scenarios for the cuprates: Sum rule consistent response functions of the pseudogap

TL;DR

This paper unifies the Fermi arcs and pockets models for cuprates' pseudogap phase, demonstrating their formal similarity and incorporating vertex corrections to improve the physical accuracy of response function calculations.

Contribution

It provides a unified framework for Fermi arcs and pockets scenarios, including vertex corrections consistent with sum rules, enhancing the understanding of charge response functions in cuprates.

Findings

Vertex corrections significantly impact observable calculations.

Unified treatment reveals common physics in Fermi arcs and pockets.

Charge ordering susceptibility shows double peak structure due to bosonic degrees of freedom.

Abstract

Essential to understanding the cuprate pseudogap phase is a study of the charge (and spin) response functions, which we address here via a consistent approach to the Fermi arcs and the Fermi pockets scenario of Yang, Rice and Zhang (YRZ). The two schemes are demonstrated to be formally similar, and to share a common physics platform; we use this consolidation to address the inclusion of vertex corrections which have been omitted in YRZ applications. We show vertex corrections can be easily implemented in a fashion analytically consistent with sum rules and that they yield important contributions to most observables. A study of the charge ordering susceptibility of the YRZ scenario makes their simple physics evident: they represent the inclusion of charged bosonic, spin singlet degrees of freedom, and are found to lead to a double peak structure.