Optical Conductivity and Hall Coefficient in High-Tc Superconductors: Significant Role of Current Vertex Corrections

TL;DR

This paper demonstrates that current vertex corrections are crucial for accurately modeling optical conductivity and Hall effects in high-Tc cuprates, explaining their unusual frequency and temperature behaviors.

Contribution

It introduces a comprehensive analysis of AC conductivities in high-Tc cuprates using the FLEX approximation with CVCs, highlighting their importance over the relaxation time approximation.

Findings

CVCs significantly affect optical Hall conductivity in the presence of AF fluctuations.

Experimental behaviors of the optical Hall coefficient are reproduced.

Both DC and AC transport phenomena are explained by nearly AF Fermi liquid theory.

Abstract

We study AC conductivities in high-Tc cuprates, which offer us significant information to reveal the true electronic ground states. Based on the fluctuation-exchange (FLEX) approximation, current vertex corrections (CVC's) are correctly taken into account to satisfy the conservation laws. We find the significant role of the CVC's on the optical Hall conductivity in the presence of strong antiferromagnetic (AF) fluctuations. This fact leads to the failure of the relaxation time approximation (RTA). As a result, experimental highly unusual behaviors, (i) prominent frequency and temperature dependences of the optical Hall coefficient, and (ii) simple Drude form of the optical Hall andge for wide range of frequencies, are satisfactorily reproduced. In conclusion, both DC and AC transport phenomena in (slightly under-doped) high-Tc cuprates can be explained comprehensively in terms of nearly AF Fermi liquid, if one take the CVC's into account.