Transport Gap in Suspended Bilayer Graphene at Zero Magnetic Field
| Autor: | Veligura, A., van Elferen, H. J., Tombros, N., Maan, J. C., Zeitler, U., van Wees, B. J. |
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| Rok vydání: | 2012 |
| Předmět: | |
| Zdroj: | Rhys. Rev. B (2012) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.85.155412 |
| Popis: | We report a change of three orders of magnitudes in the resistance of a suspended bilayer graphene flake which varies from a few k$\Omega$s in the high carrier density regime to several M$\Omega$s around the charge neutrality point (CNP). The corresponding transport gap is 8 meV at 0.3 K. The sequence of appearing quantum Hall plateaus at filling factor $\nu=2$ followed by $\nu=1$ suggests that the observed gap is caused by the symmetry breaking of the lowest Landau level. Investigation of the gap in a tilted magnetic field indicates that the resistance at the CNP shows a weak linear decrease for increasing total magnetic field. Those observations are in agreement with a spontaneous valley splitting at zero magnetic field followed by splitting of the spins originating from different valleys with increasing magnetic field. Both, the transport gap and $B$ field response point toward spin polarized layer antiferromagnetic state as a ground state in the bilayer graphene sample. The observed non-trivial dependence of the gap value on the normal component of $B$ suggests possible exchange mechanisms in the system. Comment: 8 pages, 5 figures |
| Databáze: | arXiv |
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