Universal scaling of c-axis dc conductivity for the underdoped hightemperature cuprate superconductors

TL;DR

This paper reveals a universal scaling law for the c-axis dc conductivity in underdoped high-temperature cuprate superconductors, highlighting three intrinsic processes that govern their anisotropic transport properties.

Contribution

It introduces a universal doping-dependent scaling of c-axis conductivity, identifying three fundamental processes underlying transport in all HTCSs.

Findings

{ ext{σ}c} scales universally with doping at optimal levels

Three intrinsic processes contribute to c-axis transport

The scaling behavior applies across different HTCS materials

Abstract

Coexistence of the "metallic-like" in-plane and the "semiconducting-like" out-of-plane (caxis) dc conductivities ({\sigma}c), generating a huge anisotropy in the underdoped hightemperature cuprate superconductors (HTCS), defies our current understanding of metal. In this report we present an intrinsic doping dependence of {\sigma}c. We find that the {\sigma}c for the underdoped HTCS is universally scaled to the {\sigma}c at the optimal doped-hole concentration. The universal scaling behavior suggests that there are three intrinsic processes contribute to {\sigma}c: (i) the doping-dependent-activated gap; (ii) the exponential doping dependences and (iii) the tunneling between adjacent CuO2 block layers. They are the essential underlying characteristics of the c-axis transport for all HTCSs.