Universal Superconductivity in FeTe and All-Iron-Based Ferromagnetic Superconductor Heterostructures

TL;DR

This paper reports the creation of iron-based heterostructures where ferromagnetism and high-temperature superconductivity coexist, revealing that FeTe can be driven into a superconducting state through chemical proximity effects, opening new avenues for superconducting technologies.

Contribution

First demonstration of fully iron-based SC/FM heterostructures with robust coexistence of ferromagnetism and superconductivity, and discovery of universal chemical proximity effects in FeTe films.

Findings

Fe(Te,Se) and Fe3GeTe2 heterostructures exhibit coexistence of FM and high-Tc SC.

Chemical proximity effect can induce superconductivity in non-superconducting FeTe.

FeTe's ground state is close to superconductivity, tunable by various perturbations.

Abstract

Ferromagnetism (FM) and superconductivity (SC) are two of the most famous macroscopic quantum phenomena. However, nature normally does not allow SC and FM to coexist without significant degradation. Here, we introduce the first fully iron-based SC/FM heterostructures, composed of Fe(Te,Se) and Fe3GeTe2, and show that in this platform strong FM and high-temperature SC robustly coexist. We subsequently discover that chemical proximity effect from neighboring layers can universally drive the otherwise non-superconducting FeTe films into a SC state. This suggests that the ground state of FeTe is so close to the SC state that it could be driven in and out of the SC state with various other perturbations. Altogether, this shows that Fe-Te-based heterostructures provide a unique opportunity to manipulate magnetism, superconductivity and topological physics, paving the way toward new superconducting technologies.