Dirac electrons in a dodecagonal graphene quasicrystal

Sung Joon Ahn, Pilkyung Moon, Tae Hoon Kim, Hyun Woo Kim, Ha Chul Shin, Eun Hye Kim, Hyun Woo Cha, Se-Jong Kahng, Philip Kim, Mikito Koshino, Young Woo Son, Cheol Woong Yang, Joung Real Ahn

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29 Citations (Scopus)

Abstract

Quantum states of quasiparticles in solids are dictated by symmetry. We experimentally demonstrate Dirac electrons in a two-dimensional quasicrystal without translational symmetry. A dodecagonal quasicrystalline order was realized by epitaxial growth of twisted bilayer graphene rotated exactly 30°. The graphene quasicrystal was grown up to a millimeter scale on an SiC (0001) surface while maintaining the single rotation angle over an entire sample and was successfully isolated from a substrate, demonstrating its structural and chemical stability under ambient conditions. Multiple Dirac cones replicated with the 12-fold rotational symmetry were observed in angle-resolved photoemission spectra, which revealed anomalous strong interlayer coupling with quasi-periodicity. Our study provides a way to explore physical properties of relativistic fermions with controllable quasicrystalline orders.

Original languageEnglish
JournalScience
DOIs
Publication statusAccepted/In press - 2018 Jun 28

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Cite this

Ahn, S. J., Moon, P., Kim, T. H., Kim, H. W., Shin, H. C., Kim, E. H., Cha, H. W., Kahng, S-J., Kim, P., Koshino, M., Son, Y. W., Yang, C. W., & Ahn, J. R. (Accepted/In press). Dirac electrons in a dodecagonal graphene quasicrystal. Science. https://doi.org/10.1126/science.aar8412