Unconventional Superconductivity and Density Waves in Twisted Bilayer Graphene
Name
PhysRevX.8.041041.pdf
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1018.84 KB
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Checksum (MD5)
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Author(s)
Isobe, Hiroki
Yuan, Noah F. Q.
Fu, Liang
Date Issued
December 2018
Journal
Physical Review X
Publisher
American Physical Society
Citation
Isobe, Hiroki, et al. “Unconventional Superconductivity and Density Waves in Twisted Bilayer Graphene.” Physical Review X, vol. 8, no. 4, Dec. 2018. © 2018 American Physical Society
Version
Final published version
Abstract
We study electronic ordering instabilities of twisted bilayer graphene around the filling of n=2 electrons per supercell, where correlated insulator state and superconductivity have been recently observed. Motivated by the Fermi surface nesting and the proximity to Van Hove singularity, we introduce a hot-spot model to study the effect of various electron interactions systematically. Using the renormalization group method, we find that d or p-wave superconductivity and charge or spin density wave emerge as the two types of leading instabilities driven by Coulomb repulsion. The density-wave state has a gapped energy spectrum around n=2 and yields a single doubly degenerate pocket upon doping to n>2. The intertwinement of density wave and superconductivity and the quasiparticle spectrum in the density-wave state are consistent with experimental observations. Subject Areas: Condensed Matter Physics, Superconductivity
MIT Department
Massachusetts Institute of Technology. Department of Physics
Terms of Use
Creative Commons Attribution
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1103/PhysRevX.8.041041
