Interface-Induced Superconductivity in Quantum Anomalous Hall-Iron Chalcogenide Heterostructures

When two different electronic materials are brought together, the resultant interface often shows unexpected quantum phenomena, including interfacial superconductivity and Fu-Kane topological superconductivity. In this work, we use molecular beam epitaxy (MBE) to synthesize heterostructures formed by interfacing two magnetic materials, a ferromagnetic topological insulator with the quantum anomalous Hall (QAH) state and an antiferromagnetic iron chalcogenide (FeTe). We demonstrate the coexistence of superconductivity, ferromagnetism, and topological band structure in these QAH/FeTe heterostructures, the three essential ingredients of chiral topological superconductivity. Moreover, we find that the upper critical magnetic field is anisotropic near the superconducting temperature T_c but becomes isotropic and exceeds the Pauli paramagnetic limit for conventional superconductors at low temperatures, implying an unusual superconducting pairing mechanism. The QAH/FeTe heterostructures with robust superconductivity and atomically sharp interfaces provide an ideal platform for the exploration of chiral topological superconductivity and Majorana physics, constituting an important step toward scalable topological quantum computation.