Kohn-Luttinger Superconductivity in Twisted Bilayer Graphene
[EN] We show that the recently observed superconductivity in twisted bilayer graphene (TBG) can be explained as a consequence of the Kohn-Luttinger (KL) instability which leads to an effective attraction between electrons with originally repulsiveinteraction. Usually, the KL instability takes place...
| Autores: | , |
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| Formato: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2019 |
| País: | España |
| Recursos: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/174829 |
| Acesso em linha: | http://hdl.handle.net/10261/174829 |
| Access Level: | acceso abierto |
| Palavra-chave: | Superconductivity Twisted Bilayer Graphene (TBG) Kohn-Luttinger (KL) instability |
| Resumo: | [EN] We show that the recently observed superconductivity in twisted bilayer graphene (TBG) can be explained as a consequence of the Kohn-Luttinger (KL) instability which leads to an effective attraction between electrons with originally repulsiveinteraction. Usually, the KL instability takes place at extremely low energy scales, but in TBG, a doubling and subsequent strong coupling of the van Hove singularities (vHS)intheelectronicspectrumoccursasthemagicangleisapproached,leadingtoextendedsaddlepoints in the highest valence band with almost perfect nesting between states belonging to different valleys. The highly anisotropic screening induces an effective attraction in a p-wave channel with odd parity under the exchange of the two disjoined patches of the Fermi line. We also predict the appearance of a spin-density waveinstability,adjacenttothesuperconductingphase,andtheopeningofagapintheelectronicspectrum from the condensation of spins with wave vector corresponding to the nesting vector close to the vHS. |
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