Resistivity phase diagram of cuprates revisited

TL;DR

This study revisits the resistivity phase diagram of cuprates, analyzing temperature and doping dependence in Hg1201, and supports a universal model linking inhomogeneity and transport properties across different compounds.

Contribution

It provides a detailed validation of a phenomenological model for cuprate transport, emphasizing a universal structural origin of inhomogeneity and challenging quantum critical point theories.

Findings

Model accurately describes resistivity data in Hg1201.

Little variation in inhomogeneity gap across different cuprates.

Results suggest inhomogeneity is structurally inherent, not disorder-related.

Abstract

The phase diagram of the cuprate superconductors has posed a formidable scientific challenge for more than three decades. This challenge is perhaps best exemplified by the need to understand the normal-state charge transport as the system evolves from Mott insulator to Fermi-liquid metal with doping. Here we report a detailed analysis of the temperature (T) and doping (p) dependence of the planar resistivity of simple-tetragonal HgBa$_2$CuO$_{4+\delta}$ (Hg1201), the single-CuO$_2$-layer cuprate with the highest optimal $T_c$. The data allow us to test a recently proposed phenomenological model for the cuprate phase diagram that combines a universal transport scattering rate with spatially inhomogeneous (de)localization of the Mott-localized hole. We find that the model provides an excellent description of the data. We then extend this analysis to prior transport results for several other cuprates, including the Hall number in the overdoped part of the phase diagram, and find little compound-to-compound variation in (de)localization gap scale. The results point to a robust, universal structural origin of the inherent gap inhomogeneity that is unrelated to doping-related disorder. They are inconsistent with the notion that much of the phase diagram is controlled by a quantum critical point, and instead indicate that the unusual electronic properties exhibited by the cuprates are fundamentally related to strong nonlinearities associated with subtle nanoscale inhomogeneity.