Proximity Magnetism in Mn(Bi,Sb)₂Te₄-(Bi,Sb)₂Te₃/MnTe Natural Heterostructures

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Magnetic topological insulators offer pathways to couple topological band structures with spin configurations.
• This coupling is crucial for advancing spintronic devices and magnetoelectric functionalities.
• Understanding interfacial effects is key to harnessing these properties.

Purpose of the Study:

• To investigate the structural and magnetic properties of MnTe interfaced with (Bi,Sb)2Te3.
• To explore the combination of magnetic and topological orders in the resulting heterostructures.
• To demonstrate the potential for efficient spin-orbit torque switching.

Main Methods:

• Scanning transmission electron microscopy (STEM) for structural analysis.
• Depth-sensitive polarized neutron reflectometry (DSPN) for magnetic characterization.
• Magnetotransport experiments and quantum magnetism simulations.

Main Results:

• Self-organized Mn(Bi,Sb)2Te4 septuple lamellae formed within (Bi,Sb)2Te3 quintuple layers.
• Demonstrated coupling of magnetic and topological orders in Mn(Bi,Sb)2Te4-(Bi,Sb)2Te3 heterostructures.
• Observed anomalous Hall effect mediated by Mn(Bi,Sb)2Te4 at the interface, with an enhanced Néel temperature exceeding 200 K.
• Achieved robust spin-orbit torque switching at a low critical current density of 3 × 10^5 A cm^-2.

Conclusions:

• Naturally formed Mn(Bi,Sb)2Te4-(Bi,Sb)2Te3 heterostructures exhibit significant magnetic and topological proximity effects.
• The engineered interface enables efficient, field-free spin-orbit torque switching.
• These findings hold promise for practical spintronic applications.