Tunable Spin Exchange Splitting in Graphene-Perovskite Oxide Heterostructure

A heterostructure composed of 2D layered material (2DLM) and perovskite transition metal oxide possess great promise for next-generation hybrid material with synergetic physical and chemical properties [1]. For spintronics applications, for example, multifunctional devices with low power consumption and long-distance quantum spin transport might be realized using the hybrid structure. Particularly, the heterostructure let us imagine a gate-tunable magnetic 2DLM, in which the magnetization is induced by magnetic proximity effect. Using graphene as a 2DLM, we demonstrate that the graphene coupled to a ferromagnetic insulating layer of LaCoO₃ exhibit a systematic, controllable spin exchange splitting. The magnetic ground state of Dirac electrons in graphene with spin exchange splitting shift the quantum Hall plateau and Shubnikov-de Haas quantum oscillation in the gate field induced transport behavior. In addition, we directly presented the evidence of the spin splitting via the existence of two Fermi surfaces in graphene and derivation of finite spin splitting energy owing to the proximity effect of the ferromagnetic LaCoO₃. The graphene/LaCoO₃ heterostructure with spin exchange splitting provides a unique opportunity for exploring functional spin behavior linked to the transport behavior, for next-generation of spin memory devices.<br/>[1] Kang <i>et al.</i>, <i>Adv. Mater.</i> <b>31</b>, 1803732 (2019)