Superconductivity, correlated insulators, and Wess–Zumino–Witten terms in twisted bilayer graphene

@article{Christos2020SuperconductivityCI,
  title={Superconductivity, correlated insulators, and Wess–Zumino–Witten terms in twisted bilayer graphene},
  author={Maine Christos and Subir Sachdev and Mathias S. Scheurer},
  journal={Proceedings of the National Academy of Sciences},
  year={2020},
  volume={117},
  pages={29543 - 29554}
}
Significance When the twist angle between two layers of graphene is close to 1.1°, the energy of an electron becomes nearly independent of its momentum, and the dominant Coulomb repulsion between the electrons leads to remarkable effects. Experiments have shown novel superconducting and insulating states. We propose here that these states are linked by a topological quantal phase, which is an analog of the Wess–Zumino–Witten term of high-energy physics. This term links spatiotemporal textures… 
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