• Corpus ID: 244773557

Charge order and antiferromagnetism in twisted bilayer graphene from the variational cluster approximation

@inproceedings{Pahlevanzadeh2021ChargeOA,
  title={Charge order and antiferromagnetism in twisted bilayer graphene from the variational cluster approximation},
  author={Bahareh Pahlevanzadeh and Peyman Sahebsara and David S'en'echal},
  year={2021}
}
Abstract We study the possibility of charge order at quarter filling and antiferromagnetism at halffilling in a tight-binding model of magic angle twisted bilayer graphene. We build on the model proposed by Kang and Vafek [1], relevant to a twist angle of 1.30◦, and add on-site and extended density-density interactions. Applying the variational cluster approximation with an exact-diagonalization impurity solver, we find that the system is indeed a correlated (Mott) insulator at fillings 4 , 1 2… 

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SHOWING 1-10 OF 22 REFERENCES
Unconventional superconductivity in magic-angle graphene superlattices
TLDR
The realization of intrinsic unconventional superconductivity is reported—which cannot be explained by weak electron–phonon interactions—in a two-dimensional superlattice created by stacking two sheets of graphene that are twisted relative to each other by a small angle.
Chiral triplet superconductivity on the graphene lattice
Motivated by the possibility of superconductivity in doped graphene sheets, we investigate superconducting order in the extended Hubbard model on the two-dimensional graphene lattice using the
Emergent D6 symmetry in fully relaxed magic-angle twisted bilayer graphene
We present a tight-binding calculation of a twisted bilayer graphene at magic angle $\theta\sim 1.08^\circ$, allowing for full, in- and out-of-plane, relaxation of the atomic positions. The resulting
Resilience of d-wave superconductivity to nearest-neighbor repulsion
Many theoretical approaches find d-wave superconductivity in the prototypical one-band Hubbard model for high-temperature superconductors. At strong-coupling (U > W, where U is the on-site repulsion
Symmetry, Maximally Localized Wannier States, and a Low-Energy Model for Twisted Bilayer Graphene Narrow Bands
We build symmetry adapted maximally localized Wannier states, and construct the low energy tight binding model for the four narrow bands of the twisted bilayer graphene. We do so when the twist angle
Correlated insulator behaviour at half-filling in magic-angle graphene superlattices
TLDR
It is shown experimentally that when this angle is close to the ‘magic’ angle the electronic band structure near zero Fermi energy becomes flat, owing to strong interlayer coupling, and these flat bands exhibit insulating states at half-filling, which are not expected in the absence of correlations between electrons.
Electronic properties of asymmetrically doped twisted graphene bilayers
Rotated graphene bilayers form an exotic class of nanomaterials with fascinating electronic properties governed by the rotation angle $\ensuremath{\theta}$. For large rotation angles, the electron
Flat bands in slightly twisted bilayer graphene: Tight-binding calculations
The presence of flat bands near Fermi level has been proposed as an explanation for high transition temperature superconductors. The bands of graphite are extremely sensitive to topological defects
Topological Superconductivity in Twisted Multilayer Graphene.
TLDR
A minimal Hubbard model for electronically driven superconductivity in a correlated flat miniband resulting from the superlattice modulation of a twisted graphene multilayer is studied, identifying two candidates in this class, which are both topological superconductors.
Phases of a phenomenological model of twisted bilayer graphene
We propose a lattice scale two-band generalized Hubbard model as a caricature of the electronic structure of twisted bilayer graphene. Various possible broken symmetry phases can arise, including a
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