| AVS 58th Annual International Symposium and Exhibition | |
| Graphene and Related Materials Focus Topic | Tuesday Sessions |
| Session GR+MI-TuA |
| Session: | Graphene: Magnetic Properties and Spin-Dependent Phenomena |
| Presenter: | Takahiro Kondo, University of Tsukuba, Japan |
| Authors: | T. Kondo, University of Tsukuba, Japan D. Guo, University of Tsukuba, Japan T. Machida, University of Tsukuba, Japan T. Suzuki, University of Tsukuba, Japan K. Iwatake, University of Tsukuba, Japan S. Okada, University of Tsukuba, Japan J. Nakamura, University of Tsukuba, Japan |
| Correspondent: | Click to Email |
Under the external magnetic field, carriers of graphene are quantized to show an unusual Landau level (LL) energy spectrum due to mass-less Dirac fermions (DFs).1 The LL energies are not equally spaced and include a characteristic zero-energy state (the n = 0 LL) contrary to the case of normal metals or two-dimensional electron gases. As a result, anomalous quantum Hall effect of graphene has been observed.2, 3 The quantization of the graphene carrier also occurs without external magnetic field if the appropriate strain is induced.4,5Here, we report spontaneous LLs formation of mass-less DFs on potassium intercalated graphite (K-Graphite) and nitrogen-doped graphite (N-Graphite) under zero external magnetic field with the use of scanning tunneling spectroscopy (STS). On the basis of the calculation with the density functional theory, the top-most graphene layer is found to be decoupled with the graphite due to the partial intercalation of potassium atom or nitrogen-doping on graphite. Partially decoupled graphene layer has a sufficient strain to generate the pseudo-magnetic field with about 280 T and 60 T for K-Graphite and N-Graphite, respectively, leading to the LLs formation on the top-most graphene layer on graphite.
1. A. H. Castro Neto et al., Rev. Mod. Phys. 81 (2009) 109.
2. K. S. Novoselov et al., Nat Phys. 2 (2006) 177.3. K. S. Novoselov et al., Science. 306 (2004) 666.
4. F. Guinea et al., Nat Phys. 6 (2010) 30.
5. N. Levy et al., Science. 329 (2010) 544.