Unusual Metallic Conductivity of Underdoped and Optimally Doped Cuprates: Evidence for Competing Fermi-Liquid and Pairing Pseudogap Effects

TL;DR

This paper proposes that the unusual metallic conductivity in underdoped and optimally doped cuprates arises from a competition between Fermi-liquid behavior and pairing pseudogap effects, modeled through large polarons and precursor pairing.

Contribution

It introduces a scenario where large polarons form a Fermi-liquid and Cooper-like pairs below a crossover temperature, explaining anomalies in resistivity with a theoretical model that aligns with experimental data.

Findings

Resistivity anomalies are due to competing Fermi-liquid and pairing effects.

Model fits well with experimental resistivity data.

Characterizes high-$T_c$ cuprates with intermediate coupling.

Abstract

We propose a possible scenario for the new metallic conductivity of underdoped and optimally doped cuprates. Charge carriers are assumed to be large polarons which form a Fermi-liquid and Cooper-like pairs below a crossover tempurature $T^{\ast}$. We use the Boltzmann equation to calculate the conductivity of self-trapped carriers and the resistivity $\rho$ as a function of temperature and doping for different cuprates. We show that various anomalies in $\rho(T)$ below $T^{\ast}$ are caused by the competing Fermi-liquid and BCS-like precursor pairing effects. Our results for $\rho$ fit well with existing experiments and characterize high-$T_c$ cuprates with an intermediate-coupling.