Surface states modulated exchange interaction in Bi2Se3/thulium iron garnet heterostructures* *Project supported by the National Key Basic Research Project of China (Grant No. 2016YFA0300600), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB33020300), and the National Natural Science Foundation of China (Grant Nos. 11604375 and 11874416).

Abstract

We investigate the modulation of magnetic anisotropy of thulium iron garnet (TmIG) films by interfaced Bi2Se3 thin films. High quality epitaxial growth of Bi2Se3 films has been achieved by molecular beam epitaxy on TmIG films. By the method of ferromagnetic resonance, we find that the perpendicular magnetic anisotropy (PMA) of TmIG can be greatly strengthened by the adjacent Bi2Se3 layer. Moreover, the competition between topological surface states and thickness dependent bulk states of Bi2Se3 gives rise to the modulation of PMA of the Bi2Se3/TmIG heterostructures. The interfacial interaction can be attributed to the enhanced exchange coupling between Fe3+ ions of TmIG mediated by topological surface electrons of Bi2Se3.