Coexistence of superconductivity and ferromagnetism in two dimensions

TL;DR

This paper reports the coexistence of superconductivity and ferromagnetism at the two-dimensional interface between LaAlO3 and SrTiO3, revealing complex charge carrier behavior and tunable magnetic and superconducting properties.

Contribution

It provides experimental evidence of coexistence of superconductivity and ferromagnetism in a 2D interface system, a phenomenon previously observed only in bulk materials.

Findings

Evidence of coexistence of superconductivity and ferromagnetism at LAO/STO interface

Identification of two distinct charge carrier bands affecting conductivity

Electric field sensitivity enables control over magnetic and superconducting states

Abstract

Ferromagnetism is usually considered to be incompatible with conventional superconductivity, as it destroys the singlet correlations responsible for the pairing interaction. Superconductivity and ferromagnetism are known to coexist in only a few bulk rare-earth materials. Here we report evidence for their coexistence in a two-dimensional system: the interface between two bulk insulators, LaAlO$_3$ (LAO) and SrTiO$_3$ (STO), a system that has been studied intensively recently. Magnetoresistance, Hall and electric-field dependence measurements suggest that there are two distinct bands of charge carriers that contribute to the interface conductivity. The sensitivity of properties of the interface to an electric field make this a fascinating system for the study of the interplay between superconductivity and magnetism.