Unusual behavior of cuprates explained by heterogeneous charge localization

TL;DR

This paper introduces a simple inhomogeneous model explaining various phases and transitions in cuprate high-temperature superconductors by describing hole localization and delocalization, unifying many experimental observations.

Contribution

It presents a percolative inhomogeneous Mott-like model that captures key experimental phenomena in cuprates, providing a unified explanation for their complex phase diagram.

Findings

The model explains the doping and temperature dependence of the pseudogap.

It accounts for the linear temperature dependence of resistivity in the strange-metal phase.

The model describes the doping dependence of superfluid density.

Abstract

The cuprate high-temperature superconductors are among the most intensively studied materials, yet essential questions regarding their principal phases and the transitions between them remain unanswered. Generally thought of as doped charge-transfer insulators, these complex lamellar oxides exhibit pseudogap, strange-metal, superconducting and Fermi-liquid behaviour with increasing hole-dopant concentration. Here we propose a simple inhomogeneous Mott-like (de)localization model wherein exactly one hole per copper-oxygen unit is gradually delocalized with increasing doping and temperature. The model is percolative in nature, with parameters that are experimentally constrained. It comprehensively captures pivotal unconventional experimental results, including the temperature and doping dependence of the pseudogap phenomenon, the strange-metal linear temperature dependence of the planar resistivity, and the doping dependence of the superfluid density. The success and simplicity of our model greatly demystify the cuprate phase diagram and point to a local superconducting pairing mechanism involving the (de)localized hole.