Physical Meaning of the Current Vertex Corrections: DC and AC Transport Phenomena in High-Tc Superconductors

TL;DR

This paper explains how current vertex corrections, related to backflow effects in nearly antiferromagnetic Fermi liquids, cause non-Fermi liquid transport behaviors in high-Tc superconductors, emphasizing the failure of relaxation time approximation near quantum critical points.

Contribution

It provides a simple explanation for the prominence of backflow effects in strongly correlated systems and their impact on transport phenomena in high-Tc cuprates.

Findings

Backflow enhances Hall coefficient in nearly AF Fermi liquids.

Relaxation time approximation fails near magnetic quantum critical points.

Current vertex corrections are key to understanding non-Fermi liquid behaviors.

Abstract

Famous non-Fermi liquid-like behaviors of the transport phenomena in high-Tc cuprates (Hall coefficient, magnetoresistance, thermoelectric power, Nernst coefficient, etc) are caused by the current vertex corrections in neary antiferromagnetic (AF) Fermi liquid, which was called the backflow by Landau. We present a simple explaination why the backflow is prominent in strongly correlated systems. In nearly AF Fermi liquid, R_H is enhanced by the backflow because it changes the effective curvature of the Fermi surfaces. Therefore, the relaxation time approximation is not appricalbe to a system near a magnetic quantum critical point (QCP).