Fabrication of high-temperature quasi-two-dimensional superconductors at the interface of a ferroelectric Ba$_{0.8}$Sr$_{0.2}$TiO$_{3}$ film and an insulating parent compound of La$_{2}$CuO$_{4}$

TL;DR

This paper reports the discovery of quasi-two-dimensional superconductivity at the interface of a ferroelectric Ba$_{0.8}$Sr$_{0.2}$TiO$_3$ film and La$_2$CuO$_4$, with potential for ferroelectric control of interface superconductivity.

Contribution

First demonstration of superconductivity at the interface between a ferroelectric film and La$_2$CuO$_4$, revealing a new approach to interface superconductivity control.

Findings

Superconductivity observed at the Ba$_{0.8}$Sr$_{0.2}$TiO$_3$/La$_2$CuO$_4$ interface.

Transition temperature T$_c$ approximately 30K.

Superconductivity confined near the interface, with quasi-two-dimensional characteristics.

Abstract

We report the first observation of superconductivity in heterostructure consisting of an insulating ferroelectric film (Ba$_{0.8}$Sr$_{0.2}$TiO$_3$) grown on an insulating parent compound of La$_2$CuO$_4$ with [001] orientation. The heterostructure was prepared by magnetron sputtering on a non-atomically-flat surface with inhomogeneities of the order of 1-2 nm. The measured superconducting transition temperature T$_c$ is about 30K. We have shown that superconductivity is confined near the interface region. Application of a weak magnetic field perpendicular to the interface leads to the appearance of the finite resistance. That confirms the quasi-two-dimensional nature of the superconductive state. The proposed concept promises ferroelectrically controlled interface superconductivity which offers the possibility of novel design of electronic devices.