On the vertex corrections in antiferromagnetic spin fluctuation theories

TL;DR

This paper critiques recent calculations of vertex corrections in the spin-fermion model for cuprates, clarifying discrepancies and the physical origin of the differences in results.

Contribution

It provides a critical analysis of previous vertex correction calculations, offering clarification on their physical interpretation and sign.

Findings

Recent calculations overestimate vertex corrections

Clarification of the physical origin of discrepancies

Discussion on the sign of vertex corrections

Abstract

We argue that recent calculations by Amin and Stamp (PRL 77, 301 (1996); cond-mat/9601086) overestimate the strength of the vertex corrections in the spin-fermion model for cuprates. We clarify the physical origin of the apparent discrepancy between their results and earlier calculations. We also comment on the relative sign of the vertex correction.