Dirac Electrons in a Dodecagonal Graphene Quasicrystal

Autor: Ahn, Sung Joon, Moon, Pilkyung, Kim, Tae-Hoon, Kim, Hyun-Woo, Shin, Ha-Chul, Kim, Eun Hye, Cha, Hyun Woo, Kahng, Se-Jong, Kim, Philip, Koshino, Mikito, Son, Young-Woo, Yang, Cheol-Woong, Ahn, Joung Real
Rok vydání: 2018
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1126/science.aar8412
Popis: Quantum states of quasiparticles in solids are dictated by symmetry. Thus, a discovery of unconventional symmetry can provide a new opportunity to reach a novel quantum state. Recently, Dirac and Weyl electrons have been observed in crystals with discrete translational symmetry. Here we experimentally demonstrate Dirac electrons in a two-dimensional quasicrystal without translational symmetry. A dodecagonal quasicrystal was realized by epitaxial growth of twisted bilayer graphene rotated exactly 30 degree. The graphene quasicrystal was grown up to a millimeter scale on 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 cone replicated with the 12-fold rotational symmetry were observed in angle resolved photoemission spectra, showing its unique electronic structures with anomalous strong interlayer coupling with quasi-periodicity. Our study provides a new way to explore physical properties of relativistic fermions with controllable quasicrystalline orders.
Comment: 20 pages, 4 figures
Databáze: arXiv
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