Magnetoresistance oscillations arising from edge-localized electrons in low-defect graphene antidot-lattices

Abstract

The so-called zigzag edge of graphenes has localized and strongly spin-polarized electrons. However, magnetoresistance (MR) behavior associated with the edge electrons has not been reported in graphenes. Here, we measure MR of graphene antidot-lattices, honeycomb-like arrays of hexagonal antidots with a large ensemble of hydrogen-terminated and low-defect antidot edges, prepared by a nonlithographic method using nanoporous alumina templates. We find anomalous MR oscillations arising from localized electron spins existing at the antidot edges. These are promising for realization of spintronic devices.

Electronic Properties of Nanopore Edges of Ferromagnetic Graphene Nanomeshes at High Carrier Densities under Ionic-Liquid Gating

“…In this light, a large spin current was experimentally observed using Zeeman splitting in high-quality bulk graphenes positioned on h-boron-nitride (BN) [27]. We have also reported possible spin-based phenomena arising from the pore edges of ~5-layer FM-GNMs [28].…”

“…In a previous work on FM-GNMs with nearly identical structure parameters as those in the present one but without the ionic-liquid gate, a commensurability MR peak was observed at B ~ 1.2 T [28]. From the expression ( ) Figure 3 shows the MR (R xx ) as a function of V ig .…”

“…, where h and e denote Planck's constant and the electron charge, respectively [28]. A variety of interesting MR phenomena has been observed depending on the correlation of 2R c with φ (the pore diameter) and a (the diameter of the unit cell).…”

“…Indeed, a variety of spin-related phenomena have been predicted based on the study of the edge spins of graphene [6,[24][25][26][27][28]. For instance, half-metallicity was predicted in GNRs with antiferromagnetic (AF) spin alignment at two zigzag edges [6].…”

Hofstadter butterflies and magnetically induced band-gap quenching in graphene antidot lattices

“…Recently, however, graphene antidot lattices (GALs) have been proposed 3,4 and magnetotransport studies have been realized experimentally. [5][6][7][8] Whereas GaAs antidots are typically produced by dry etching or local ion implantation in molecular beam epitaxy grown heterostructures, GALs are produced by simply etching arrays of holes into graphene sheets placed on suitable insulating substrates. Etch masks can be fabricated using either e-beam lithography or block copolymers.…”