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Dirac Cone Spin Polarization of Graphene by Magnetic Insulator Proximity Effect Probed with Outermost Surface Spin Spectroscopy |
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| Authors: | Seiji Sakai Sergei V Erohin Zakhar I Popov Satoshi Haku Takahiro Watanabe Yoichi Yamada Shiro Entani Songtian Li Pavel V Avramov Hiroshi Naramoto Kazuya Ando Pavel B Sorokin Yasushi Yamauchi |
| Affiliation: | 1. Quantum Beam Science Research Directorate/QST Future laboratory, National Institutes for Quantum and Radiological Science and Technology QST, Naka, Ibaraki, Japan;2. Research Center for Advanced Measurement and Characterization, National Institute for Materials Science, Tsukuba, Ibaraki, Japan;3. Faculty of Pure and Applied Science, Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki, Japan;4. Laboratory of Inorganic Nanomaterials, National University of Science and Technology MISiS, Moscow, Russian Federation;5. Department of Applied Physics and Physico‐Informatics, Keio University, Kohoku‐ku, Yokohama, Japan;6. Department of Chemistry, College of Natural Sciences, Kyungpook National University, Daegu, Republic of Korea;7. PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan |
| Abstract: | The effects of the proximity contact with magnetic insulator on the spin‐dependent electronic structure of graphene are explored for the heterostructure of single‐layer graphene (SLG) and yttrium iron garnet Y3Fe5O12 (YIG) by means of outermost surface spin spectroscopy using a spin‐polarized metastable He atom beam. In the SLG/YIG heterostructure, the Dirac cone electrons of graphene are found to be negatively spin polarized in parallel to the minority spins of YIG with a large polarization degree, without giving rise to significant changes in the π band structure. Theoretical calculations reveal the electrostatic interfacial interactions providing a strong physical adhesion and the indirect exchange interaction causing the spin polarization of SLG at the interface with YIG. The Hall device of the SLG/YIG heterostructure exhibits a nonlinear Hall resistance attributable to the anomalous Hall effect, implying the extrinsic spin–orbit interactions as another manifestation of the proximity effect. |
| Keywords: | graphene spintronics magnetic insulators outermost surface spin spectroscopy proximity effect spin polarization |