Superconductivity in FeTe-Based Heterostructures

FeTe is an antiferromagnetic iron chalcogenide metal with a crystal structure identical to FeSe. Unlike superconducting FeSe, FeTe does not exhibit superconductivity, which is usually attributed to its bi-collinear antiferromagnetic order. In this work, we employed molecular beam epitaxy to synthesize a series of FeTe-based heterostructures, including (Bi,Sb)₂Te₃/FeTe, Cr-doped (Bi,Sb)₂Te₃/FeTe, MnBi₂Te₄/FeTe, CrTe₂/FeTe, and SnTe/FeTe. Our electrical transport measurements reveal that these heterostructures show superconductivity with a critical superconducting transition temperature of ~11 K. Moreover, by performing in-situ spin-polarized scanning tunneling microscopy/spectroscopy measurements, we observed that a superconducting gap emerges once the bi-collinear antiferromagnetic order in the FeTe layer is suppressed. This work provides new insights into the mechanisms responsible for superconductivity in FeTe-based heterostructures.