Coherence and superconductivity in coupled one-dimensional chains: a case study of YBa$_{2}$Cu$_{3}$O$_{y}$

TL;DR

This study investigates the infrared response of Cu-O chains in YBa₂Cu₃O_y, revealing one-dimensional transport behavior and exploring how coupling to CuO₂ planes influences metallicity and superconductivity across different doping levels.

Contribution

It provides experimental evidence of Tomonaga-Luttinger liquid behavior in Cu-O chains and analyzes the impact of chain-plane coupling on superconductivity.

Findings

Power law scaling at mid-IR frequencies consistent with Tomonaga-Luttinger liquid

Chain-plane coupling influences metallicity in disordered chain fragments

Infrared response varies with doping level

Abstract

We report the infrared (IR) response of Cu-O chains in the high-$T_{c}$ superconductor YBa$_{2}$Cu$_{3}$O$_{y}$ over the doping range spanning $% y=6.28-6.75$. We find evidence for a power law scaling at mid-IR frequencies consistent with predictions for Tomonaga-Luttinger liquid, thus supporting the notion of one-dimensional transport in the chains. We analyze the role of coupling to the CuO$_{2}$ planes in establishing metallicity and superconductivity in disordered chain fragments.