Topological Insulator Bi2se3 Films On Rare Earth Iron Garnets And Their High-Quality Interfaces

The integration of quantum materials like topological insulators (TIs) with magnetic insulators (MIs) has important technological implications for spintronics and quantum computing. Here, we report excellent crystallinity of c-axis oriented epitaxial TI films of Bi2Se3 grown on MI films, a rare earth iron garnet (ReIG), such as thulium iron garnet (Tm3Fe5O12, TmIG), by molecular beam epitaxy using Se-buffered low-temperature growth technique. Strained-TmIG films with robust perpendicular magnetic anisotropy were deposited by off-axis sputtering. We demonstrated a streaky reflection high-energy electron diffraction pattern starting from the very first quintuple layer of Bi2Se3, indicating the high-quality interface between TmIG and Bi2Se3, a prerequisite for studying interfacial exchange coupling effects. The strong interfacial exchange interaction was manifested by the observation of an anomalous Hall effect in the Bi2Se3/TmIG bilayer and a shift of the ferromagnetic resonance field of TmIG induced by Bi2Se3. We have reproducibly grown high-quality Bi2Se3/ReIG and interfaces using this TI growth method, which may be applied to grow other types of van der Waals hetero-structures. Published under license by AIP Publishing.