Explaining the pseudogap through damping and antidamping on the Fermi surface by imaginary spin scattering

TL;DR

This paper investigates the pseudogap in hole-doped cuprates using a Feynman-diagrammatic approach to the Hubbard model, revealing a damping mechanism involving imaginary spin scattering that explains experimental features.

Contribution

It introduces a novel mechanism involving damping and antidamping effects from imaginary spin scattering to explain the pseudogap phenomena.

Findings

Damping of antinodal fermions due to imaginary spin-fermion vertex.

Protection of nodal Fermi arcs (antidamping) by this mechanism.

Explanation of Fermi arc cutoff and hot spot insignificance in experiments.

Abstract

The mechanism of the pseudogap observed in hole-doped cuprates remains one of the central puzzles in condensed matter physics. We analyze this phenomenon via a Feynman-diagrammatic inspection of the Hubbard model. Our approach captures the pivotal interplay between Mott localization and Fermi surface topology beyond weak-coupling spin fluctuations, which would open a spectral gap near hot spots. We show that strong coupling and particle-hole asymmetry trigger a very different mechanism: a large imaginary part of the spin-fermion vertex promotes damping of antinodal fermions and, at the same time, protects the nodal Fermi arcs (antidamping). Our analysis naturally explains puzzling features of the pseudogap observed in experiments, such as Fermi arcs being cut off at the antiferromagnetic zone boundary and the subordinate role of hot spots.