Proximity-Induced Magnetism in CrTe2/Bi2Te3 Ferromagnet-Topological Insulator Heterostructures

Topological electronics explores novel quantum properties encountered in topological insulators (TIs). TIs exhibit remarkable features, including dissipationless carrier transport through their surface states. When TIs are magnetically doped, they can display the quantum anomalous Hall effect (QAHE)—a zero-field version of the ordinary quantum Hall effect. However, due to defects associated with doping, the useful temperature range for QAHE is limited. By bringing a magnetic material close to a TI, the TI’s surface states can acquire magnetic properties via proximity-induced magnetism (PIM). We recently discovered that Mn diffusion in the leading Mn-based heterostructures can mimic the elusive PIM effect at the interface.

To address this problem, have recently studied the NiO/Bi2Te3 system with PNR, and found that despite its superb structural quality, the magnetic complexity of the NiO layer makes drawing unambiguous conclusions about PIM difficult. Here, we propose to study CrTe2/Bi2Te3 heterostructures by PNR, which have two outstanding properties. First, the 1T- CrTe2 layer has a well-defined (out-of-plane) magnetic anisotropy. Second, since the nuclear SLD of the two layers is very similar, small changes in the magnetic SLD at the interface will have a huge effect on the spin asymmetry, hopefully allowing, for the first time, to get unambiguous proof of the existence of the elusive PIM effect.