3D strain-induced superconductivity in La ₂ CuO _4+δ using a simple vertically aligned nanocomposite approach

Abstract

A long-term goal for superconductors is to increase the superconducting transition temperature, TC. In cuprates, TC 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 La2CuO4+δ + LaCuO3, 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 La2CuO4+δ films. Our proof-of-concept work represents an entirely new approach to increasing TC in cuprates or other superconductors.

Endogenous Nanoparticles Strain Perovskite Host Lattice Providing Oxygen Capacity and Driving Oxygen Exchange and CH4 Conversion to Syngas

“…Similarly, embedding noble metal nanoparticles within other inorganic crystal lattices enhances electronic transport in a manner analogue to substitutional doping [2] . Therefore, embedding metallic nanoparticles within non-metallic crystal lattices could open new possibilities to tailor materials , in particular through strain engineering, which has been shown to control multiple properties including oxide ion, electron and thermal transport [3][4][5] , catalytic reactivity [3,[6][7][8][9] and magnetic properties [10] . However, producing and controlling such nanocomposites remains challenging.…”

Revealing the Structure and Oxygen Transport at Interfaces in Complex Oxide Heterostructures via 17O NMR Spectroscopy

“…Oxide heterostructures combine two or more different phases, the interfaces of which induce novel or enhanced functional properties due to their unique local environments. 1 − 4 In particular, vertically aligned nanocomposite (VAN) films, comprising nanopillars of one phase embedded in a matrix of another, have shown great promise for applications as high-temperature superconductors, 5 − 8 ferroelectrics, 9 − 12 multiferroics, 13 data storage media, 14 , 15 and electronic/ionic conductors. 16 − 18 Unlike conventional planar multilayered heterostructures, the interfaces in VAN films are perpendicular to the substrate, resulting in significantly higher interface-to-volume ratios, more uniform strain, and control over the orthogonal transport properties, 4 , 19 leading to their potential use in, for example, micron-sized fuel cells.…”

Probing Interfaces in Complex Oxide Heterostructures via 17O Solid State NMR Spectroscopy

“…Oxide heterostructures combine two or more different phases, the interfaces of which induce novel or enhanced functional properties due to their unique local environments. [1][2][3][4] In particular, vertically aligned nanocomposite (VAN) films, comprising nanopillars of one phase embedded in a matrix of another, have shown great promise for applications as hightemperature superconductors, [5][6][7][8] ferroelectrics, [9][10][11][12] multiferroics, 13 data storage media, 14,15 and electronic/ionic conductors. [16][17][18] Unlike conventional planar multi-layered heterostructures, the interfaces in VAN films are perpendicular to the substrate, resulting in significantly higher interfaceto-volume ratios, more uniform strain, and control over the orthogonal transport properties, 4,19 leading to their potential use in, for example, micron-sized fuel cells.…”