콜로키움

[2023-1 콜로키움] 2023년 05월 17일 16:30, 안종열 교수 (성균관대학교 물리학과)
2023-05-22 16:37:32 조회수177

 Graphene Quasicrystgal and Twistronics

  • 일 시 : 2023년 05월 17일 수요일 16:30

  • 연 사 : 안 종 열 교수 (성균관대학교 물리학과)

  • 장 소 : 자연과학관 B117호

  • HOST : 조 준 형 교수님

  • 초 록

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°. 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.

KakaoTalk_20230518_145458196_02

 

 
사이트맵 닫기