• 文献标题:   Four-fold Raman enhancement of 2D band in twisted bilayer graphene: evidence for a doubly degenerate Dirac band and quantum interference
  • 文献类型:   Article
  • 作  者:   WANG YN, SU ZH, WU W, NIE S, LU XH, WANG HY, MCCARTY K, PEI SS, ROBLESHERNANDEZ F, HADJIEV VG, BAO JM
  • 作者关键词:   twisted bilayer graphene, raman scattering, quantum interference
  • 出版物名称:   NANOTECHNOLOGY
  • ISSN:   0957-4484 EI 1361-6528
  • 通讯作者地址:   Univ Houston
  • 被引频次:   9
  • DOI:   10.1088/0957-4484/25/33/335201
  • 出版年:   2014

▎ 摘  要

We report the observation of a strong 2D band Raman in twisted bilayer graphene (tBLG) with large rotation angles under 638 nm and 532 nm visible laser excitations. The 2D band Raman intensity increased four-fold as opposed to the two-fold increase observed in single-layer graphene. The same tBLG samples also exhibited rotation-dependent G-line resonances and folded phonons under 364 nm UV laser excitation. We attribute this 2D band Raman enhancement to the constructive interference between two double-resonance Raman pathways, which were enabled by a nearly degenerate Dirac band in the tBLG Moire superlattices.