Electronic Properties of Nanopore Edges of Ferromagnetic Graphene Nanomeshes at High Carrier Densities under Ionic-Liquid Gating — Oak Academic Publishing
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Electronic Properties of Nanopore Edges of Ferromagnetic Graphene Nanomeshes at High Carrier Densities under Ionic-Liquid Gating
Faculty of Science and Engineering, Aoyama Gakuin University, Sagamihara, Japan
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Faculty of Science and Engineering, Aoyama Gakuin University, Sagamihara, Japan
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Faculty of Science and Engineering, Aoyama Gakuin University, Sagamihara, Japan
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Faculty of Science and Engineering, Aoyama Gakuin University, Sagamihara, Japan
1 Faculty of Science and Engineering, Aoyama Gakuin University, Sagamihara, Japan
2 Faculty of Science and Engineering, Aoyama Gakuin University, Sagamihara, Japan
3 Faculty of Science and Engineering, Aoyama Gakuin University, Sagamihara, Japan
4 Faculty of Science and Engineering, Aoyama Gakuin University, Sagamihara, Japan
Graphene edges with a zigzag-type atomic structure can theoretically produce spontaneous spin polarization despite being a critical-metal-free material. We have demonstrated this in graphene nanomeshes (GNMs) with honeycomb-like arrays of low-defect hexagonal nanopores by observing room-temperature ferromagnetism and spin-based phenomena arising from the zigzag-pore edges. Here, we apply extremely high electric fields to the ferromagnetic (FM) GNMs using an ionic-liquid gate. A large on/off-ratio for hole current is observed for even small applied ionic-liquid gate voltages (V ig ). Observations of the magnetoresistance behavior reveal high carrier densities of ~10 13 cm -2 at large V ig values. We find a maximum conductance peak in the high - V ig region and its separation into two peaks upon applying a side-gate (in-plane external) voltage (V ex ). It is discussed that localized edge-π band with excess-density electrons induced by V ig and its spin splitting for majority and minority of spins by V ex (half-metallicity model) lead to these phenomena. The results must realize critical-element-free novel spintronic devices.
KeywordsGrapheneNanomeshEdgeSpin PolarizationMagnetismIonic-Liquid GateHigh Electric FieldsRare-Metal-Free Spintronics
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