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RESEARCH PRODUCT
Mean-field theory for superconductivity in twisted bilayer graphene
Risto OjajärviTeemu J. PeltonenTero T. Heikkiläsubject
Magic anglesuprajohtavuusFOS: Physical sciences02 engineering and technologysuperconducting order parameter01 natural sciencesSuperconductivity (cond-mat.supr-con)superconducting phase transitionCondensed Matter::Superconductivity0103 physical sciencesgrafeeni010306 general physicsPhysicsSuperconductivityCouplingta114Condensed matter physicsCondensed Matter - SuperconductivityDopingFunction (mathematics)021001 nanoscience & nanotechnologysuperconducting gapMean field theory0210 nano-technologyBilayer grapheneExcitationdescription
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 makes also 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.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2018-05-02 | Physical Review B |