Abstract
We report a first-principles investigation of electronic structure, topological bands, and electron-phonon interactions in metallic biphenylene sheets. Biphenylene is a recently synthesized -bonded carbon allotrope. We find coupling of electrons at the Fermi surface to very high frequency carbon-derived phonons, analogous to superconducting . This leads to low-temperature weak coupling superconductivity due to an unusual combination of exceptionally large logarithmically averaged phonon frequency =1369 K and moderate electron-phonon coupling. The electronic structure shows a two-band Fermi surface dominated by C orbitals and a pair of type-II tilted Dirac cones along the -Y line at the Brillouin zone boundary. Berry curvature and edge-state calculations show that monolayer biphenylene is a two-dimensional topological material. Thus, monolayer biphenylene is predicted to be a topological superconductor based on C orbitals and high-frequency phonons.
2 More- Received 25 October 2021
- Accepted 8 December 2021
DOI:https://doi.org/10.1103/PhysRevB.104.235422
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