Maximally Localized Wannier Orbitals and the Extended Hubbard Model for Twisted Bilayer Graphene
Name
PhysRevX.8.031087.pdf
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2.68 MB
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Author(s)
Koshino, Mikito
Yuan, Noah F. Q.
Koretsune, Takashi
Ochi, Masayuki
Kuroki, Kazuhiko
Fu, Liang
Date Issued
September 2018
Journal
Physical Review X
Publisher
American Physical Society
Citation
Koshino, Mikito, et al. “Maximally Localized Wannier Orbitals and the Extended Hubbard Model for Twisted Bilayer Graphene.” Physical Review X, vol. 8, no. 3, Sept. 2018. © 2018 American Physical Society
Version
Final published version
Abstract
We develop an effective extended Hubbard model to describe the low-energy electronic properties of the twisted bilayer graphene. By using the Bloch states in the effective continuum model and with the aid of the maximally localized algorithm, we construct the Wannier orbitals and obtain an effective tight-binding model on the emergent honeycomb lattice. We find that the Wannier state takes a peculiar three-peak form in which the amplitude maxima are located at the triangle corners surrounding the center. We estimate the direct Coulomb interaction and the exchange interaction between the Wannier states. At the filling of two electrons per supercell, in particular, we find an unexpected coincidence in the direct Coulomb energy between a charge-ordered state and a homogeneous state, which could possibly lead to an unconventional many-body state.
MIT Department
Massachusetts Institute of Technology. Department of Physics
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Creative Commons Attribution
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DOI of Published Version
https://doi.org/10.1103/PhysRevX.8.031087
