Infrared Properties of Electron Doped Cuprates: Tracking Normal State Gaps and Quantum Critical Behavior in Pr(2-x)Ce(x)CuO(4)

TL;DR

This study investigates the infrared properties of electron-doped cuprates, revealing a doping-dependent gap and evidence for a quantum critical point where magnetism and superconductivity coexist.

Contribution

It provides the first detailed infrared analysis of Pr(2-x)Ce(x)CuO(4) across doping levels, identifying a quantum critical point through gap behavior.

Findings

Partial gap opening up to optimal doping

Model combining spin density wave and self energy fits data

Quantum critical point at x ~ 0.17

Abstract

We report the temperature dependence of the infrared-visible conductivity of Pr(2-x)Ce(x)CuO(4) thin films. When varying the doping from a non-superconducting film (x = 0.11) to a superconducting overdoped film (x = 0.17), we observe, up to optimal doping (x = 0.15), a partial gap opening. A model combining a spin density wave gap and a frequency and temperature dependent self energy reproduces our data reasonably well. The magnitude of this gap extrapolates to zero for x ~ 0.17 indicating the coexistence of magnetism and superconductivity in this material and the existence of a quantum critical point at this Ce concentration.