Pressure induced compression of flatbands in twisted bilayer Grapheme

Bheema Lingam Chittari, Nicolas Leconte, Srivani Javvaji, Jeil Jung

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

We investigate the bandwidth compression due to out of plane pressure of the moiré flatbands near charge neutrality in twisted bilayer graphene for a continuous range of small rotation angles of up to 2.5 . The flatband bandwidth minima angles are found to grow linearly with interlayer coupling ω and decrease with Fermi velocity. Application of moderate pressure values of up to 2.5 GPa achievable through a hydraulic press should allow to access a flatband for angles as large as 1.5 instead of 1 at zero pressure. This reduction of the moiré pattern length for larger twist angles implies increase of the effective Coulomb interaction scale per moiré cell by about 50% and enhances roughly by a factor of 2 the elastic energy that resists the commensuration strains due to the moiré pattern. Our results suggest that application of pressure on twisted bilayer graphene nanodevices through a hydraulic press will notably facilitate the device preparation efforts required for exploring the ordered phases near magic angle flatbands.

Original languageEnglish
Article number015001
JournalElectronic Structure
Volume1
Issue number1
DOIs
StatePublished - Mar 2019

Keywords

  • Electronic structure
  • Flatbands
  • Moire patterns
  • Pressure
  • Twisted bilayers

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