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Tunning the tilt of the Dirac cone by atomic manipulations in 8Pmmn borophene

Yekta, Y ; Sharif University of Technology | 2023

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  1. Type of Document: Article
  2. DOI: 10.1038/s42005-023-01161-9
  3. Publisher: Nature Research , 2023
  4. Abstract:
  5. Two dimensional quantum materials possessing Dirac cones in their spectrum are fascinating due to their emergent low-energy Dirac fermions. In 8Pmmn borophene the Dirac cone is furthermore tilted, which is a proxy for spacetime geometry, since the future light-cone depends on the underlying metric. Therefore it is important to understand the microscopic origin of the tilt. Here, based on ab-initio calculations, we decipher the atomistic mechanism of the formation of tilt. First, nearest-neighbor hopping on a buckled honeycomb lattice forms an upright Dirac cone. Then, the difference in the renormalized anisotropic second-neighbor hopping, formed by virtual hoppings on one-dimensional chains of atoms, tilts the Dirac cone. We construct an accurate tight-binding model on honeycomb graph for analytical investigation, and we find that substitution of certain boron atoms by carbon provides a way to change the tilt of the cone. © 2023, The Author(s)
  6. Keywords:
  7. Two dimensional quantum materials ; Dirac cones ; Low-energy Dirac fermions ; Nearest-neighbor hopping ; Geometric Quantum Material (GQM)
  8. Source: Communications Physics ; Volume 6, Issue 1 , 2023 ; 23993650 (ISSN)
  9. URL: https://www.nature.com/articles/s42005-023-01161-9