2 research outputs found
Asymmetric Modulation on Exchange Field in a Graphene/BiFeO<sub>3</sub> Heterostructure by External Magnetic Field
Graphene, having all atoms on its
surface, is favorable to extend
the functions by introducing the spin–orbit coupling and magnetism
through proximity effect. Here, we report the tunable interfacial
exchange field produced by proximity coupling in graphene/BiFeO<sub>3</sub> heterostructures. The exchange field has a notable dependence
with external magnetic field, and it is much larger under negative
magnetic field than that under positive magnetic field. For negative
external magnetic field, interfacial exchange coupling gives rise
to evident spin splitting for <i>N</i> ≠0 Landau
levels and a quantum Hall metal state for <i>N</i> = 0 Landau
level. Our findings suggest graphene/BiFeO<sub>3</sub> heterostructures
are promising for spintronics
Electronic Coupling between Graphene and Topological Insulator Induced Anomalous Magnetotransport Properties
It
has been theoretically proposed that the spin textures of surface
states in a topological insulator can be directly transferred to graphene
by means of the proximity effect, which is very important for realizing
a two-dimensional topological insulator based on graphene. Here we
report the anomalous magnetotransport properties of graphene–topological
insulator Bi<sub>2</sub>Se<sub>3</sub> heterojunctions, which are
sensitive to the electronic coupling between graphene and the topological
surface state. The coupling between the p<sub><i>z</i></sub> orbitals of graphene and the p orbitals of the surface states on
the Bi<sub>2</sub>Se<sub>3</sub> bottom surface can be enhanced by
applying a perpendicular negative magnetic field, resulting in a giant
negative magnetoresistance at the Dirac point up to about −91%.
An obvious resistance dip in the transfer curve at the Dirac point
is also observed in the hybrid devices, which is consistent with theoretical
predictions of the distorted Dirac bands with nontrivial spin textures
inherited from the Bi<sub>2</sub>Se<sub>3</sub> surface states