Magnetic coupling mechanism of the interface in Bi₂Se₃/La_0.7Sr_0.3MnO₃

The magnetic proximity effect in Bi2Se3 (BS)/La0.7Sr0.3MnO3 (LSMO) heterostructures is studied by first-principles calculations based on the density functional theory (DFT). Two heterogeneous structures LSMO (La, Sr, O termination layer, labeled as LaSrO)/BS and LSMO (Mn, O termination layer, labeled as MnO2)/BS are configured. In the LaSrO/BS system, the larger interfacial distance (2.88 angstrom) and higher interfacial binding energy (-6.36 eV) indicate a greater degree of stability for this structure. The spin polarization density distribution and spin magnetic moment results show BS can be effectively magnetized in both heterostructures. The magnetic coupling effect and observed charge transfer in MnO2/BS are more pronounced, suggesting potential differences in the magnetic exchange mechanisms between LaSrO/BS and MnO2/BS. The projected density of states (PDOS) and spin polarizability suggest that electron exchange and orbital hybridization between Mn-3d orbitals and BS play a crucial role in inducing magnetic order in BS. In MnO2/BS, the magnetic proximity effect is stronger, and more spin electron transfer between Mn-d and Se -p orbital of BS. These results may promote the application of TIs in the spintronic devices field.