In-situ epitaxial growth of superconducting La-based bilayer cuprate thin films

TL;DR

This study demonstrates the in-situ epitaxial growth of superconducting bilayer cuprate La2CaCu2O6+b4 thin films using pure ozone, revealing superconductivity induced solely by excess oxygen without cation substitution.

Contribution

First demonstration of superconductivity in bilayer La2CaCu2O6+b4 films achieved through epitaxial growth and oxygen doping, without cation substitution.

Findings

Films show metallic behavior due to epitaxial strain.

Superconductivity observed below 30 K.

Superconductivity induced purely by excess oxygen.

Abstract

We investigate the epitaxial growth of bilayer cuprate La2CaCu2O6+\delta using pure ozone as an oxidant, and find that even the crystal with parent composition without cation substitution can show metallic behavior with the aid of epitaxial strain effect. The hole concentration is controlled simply by excess-oxygen doping, and the films grown under the optimum conditions exhibit superconductivity below 30 K. This is the first result on the superconductivity of bilayer La2CaCu2O6+\delta induced purely by the excess oxygen.