Strong- and weak-coupling mechanisms for pseudogap in electron-doped cuprates

TL;DR

This paper investigates the origins of the pseudogap in electron-doped cuprates, identifying strong-coupling short-range correlations near half-filling and weak-coupling antiferromagnetic correlations near optimal doping as key mechanisms.

Contribution

It distinguishes between strong- and weak-coupling mechanisms for the pseudogap using advanced theoretical approaches and clarifies their relevance in different doping regimes.

Findings

Pseudogap driven by short-range correlations near half-filling.

Large antiferromagnetic correlations cause the pseudogap near optimal doping.

The t-J model is unsuitable for describing the weak-coupling pseudogap.

Abstract

Using the two-particle self-consistent approach and cluster perturbation theory for the two-dimensional t-t'-t''-U Hubbard model, we discuss weak- and strong-coupling mechanisms for the pseudogap observed in recent angle resolved photoemission spectroscopy on electron-doped cuprates. In the case of the strong-coupling mechanism, which is more relevant near half-filling, the pseudogap can be mainly driven by short range correlations near the Mott insulator. In the vicinity of optimal doping, where weak-coupling physics is more relevant, large antiferromagnetic correlation lengths, seen in neutron measurements, are the origin of the pseudogap. The t-J model is not applicable in the latter case.