• 文献标题:   Electron-Phonon Coupling in a Magic-Angle Twisted-Bilayer Graphene Device from Gate-Dependent Raman Spectroscopy and Atomistic Modeling
  • 文献类型:   Article
  • 作  者:   GADELHA AC, NGUYEN VH, NETO EGS, SANTANA F, RASCHKE MB, LAMPARSKI M, MEUNIER V, CHARLIER JC, JORIO A
  • 作者关键词:   graphene, raman spectroscopy, atomistic modeling, electronphonon interaction
  • 出版物名称:   NANO LETTERS
  • ISSN:   1530-6984 EI 1530-6992
  • 通讯作者地址:  
  • 被引频次:   3
  • DOI:   10.1021/acs.nanolett.2c00905 EA JUL 2022
  • 出版年:   2022

▎ 摘  要

The importance of phonons in the strong correlation phenomena observed in twisted-bilayer graphene (TBG) at the so-called magic-angle is under debate. Here we apply gate-dependent micro-Raman spectroscopy to monitor the G band line width in TBG devices of twist angles theta = 0 degrees (Bernal), similar to 1.1 degrees (magic-angle), and similar to 7 degrees (large-angle). The results show a broad and p-/n-asymmetric doping behavior at the magic angle, in clear contrast to the behavior observed in twist angles above and below this point. Atomistic modeling reproduces the experimental observations in close connection with the joint density of electronic states in the electron-phonon scattering process, revealing how the unique electronic structure of magic-angle TBGs influences the electron-phonon coupling and, consequently, the G band line width. Overall, the value of the G band line width in magic-angle TBG is larger when compared to that of the other samples, in qualitative agreement with our calculations.