3D strain-induced superconductivity in La<sub>2</sub>CuO<sub>4+δ</sub> using a simple vertically aligned nanocomposite approach.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31032414.
- Also identified by DOI 10.1126/sciadv.aav5532 and PMC identifier 6486216.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
A long-term goal for superconductors is to increase the superconducting transition temperature, <i>T</i> <sub>C</sub>. In cuprates, <i>T</i> <sub>C</sub> depends strongly on the out-of-plane Cu-apical oxygen distance and the in-plane Cu-O distance, but there has been little attention paid to tuning them independently. Here, in simply grown, self-assembled, vertically aligned nanocomposite thin films of La<sub>2</sub>CuO<sub>4+δ</sub> + LaCuO<sub>3</sub>, by strongly increasing out-of-plane distances without reducing in-plane distances (three-dimensional strain engineering), we achieve superconductivity up to 50 K in the vertical interface regions, spaced ~50 nm apart. No additional process to supply excess oxygen, e.g., by ozone or high-pressure oxygen annealing, was required, as is normally the case for plain La<sub>2</sub>CuO<sub>4+δ</sub> films. Our proof-of-concept work represents an entirely new approach to increasing <i>T</i> <sub>C</sub> in cuprates or other superconductors.