Disorder-driven quantum phase transition from antiferromagnetic metal to insulating state in multilayered high-Tc cuprate (Cu,C)Ba2Ca4Cu5Oy

TL;DR

This paper investigates the interplay of antiferromagnetic order and superconductivity in multilayered high-Tc cuprates, revealing how carrier density and disorder influence phase transitions between antiferromagnetic, insulating, and superconducting states.

Contribution

It demonstrates that the carrier density in the outer planes determines the superconducting transition temperature and shows the persistence of antiferromagnetic order in inner planes despite superconductivity in outer planes.

Findings

Superconductivity occurs at Tc=98 K in optimally-doped outer planes.

Antiferromagnetic order is present in inner planes regardless of superconductivity.

Disorder-induced carrier localization affects the antiferromagnetic state at low temperatures.

Abstract

We report on superconducting(SC) characteristics for oxygen-reduced Cu-based five-layered high-temperature superconductor (Cu,C)Ba2Ca4Cu5Oy(Cu-1245(OPT)), which includes five-fold outer planes (OP) and four-fold inner planes (IP).As a result of the reduction of the carrier density, the bulk SC for Cu-1245 (OPT) takes place at the nearly optimally-doped OP with Tc= 98 K that is different from previously-reported Cu-1245(OVD) where IP plays a primary role for the onset of SC. It gives an evidence that the carrier density of the optimally-doped layer determines its bulk Tc.Static antiferromagnetic(AFM) order is evidenced at IP's by zero-field Cu-NMR at low temperature, irrespective of the SC transition at OP's below 98K. This AFM state at IP's is characterized by a carrier localization at low temperatures due to disorder effect, whereas the carrier densities in each layer are similar to Hg-1245(OPT) where the AFM metallic state are realized in IP's. This finding reinforces the phase diagram in which the AFM metallic phase exists between AFM insulator and SC states for the case of ideally-flat CuO2 plane without disorder.