Mean-field theory for superconductivity in twisted bilayer graphene
Peltonen, T., Ojajärvi, R., & Heikkilä, T. (2018). Mean-field theory for superconductivity in twisted bilayer graphene. Physical Review B, 98(22), Article 220504(R). https://doi.org/10.1103/PhysRevB.98.220504
Published inPhysical Review B
© 2018 American Physical Society
Recent experiments show how a bilayer graphene twisted around a certain magic angle becomes superconducting as it is doped into a region with approximate flat bands. We investigate the mean-field s-wave superconducting state in such a system and show how the state evolves as the twist angle is tuned, and as a function of the doping level. We argue that part of the experimental findings could well be understood to result from an attractive electron-electron interaction mediated by electron-phonon coupling, but the flat-band nature of the excitation spectrum also makes the superconductivity quite unusual. For example, as the flat-band states are highly localized around certain spots in the structure, also the superconducting order parameter becomes strongly inhomogeneous.
PublisherAmerican Physical Society
Publication in research information system
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Related funder(s)Academy of Finland
Funding program(s)Centre of Excellence, AoF; Others, AoF
Additional information about fundingThis project was supported by Academy of Finland Key Project funding, and the Center of Excellence program (Projects No. 305256 and No. 284594). We acknowledge grants of computer capacity from the Finnish Grid and Cloud Infrastructure (persistent identifier urn:nbn:fi:research-infras-2016072533).
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