# Cascade of phase transitions and Dirac revivals in magic-angle graphene

@article{Zondiner2020CascadeOP,
title={Cascade of phase transitions and Dirac revivals in magic-angle graphene},
author={Uri Zondiner and Asaf Rozen and Daniel Rodan-Legrain and Y. Cao and Raquel Queiroz and Takashi Taniguchi and K. Watanabe and Yuval Oreg and Felix von Oppen and Ady Stern and Erez Berg and Pablo Jarillo-Herrero and Shahal Ilani},
journal={Nature},
year={2020},
volume={582},
pages={203-208}
}
Twisted bilayer graphene near the magic angle 1 – 4 exhibits rich electron-correlation physics, displaying insulating 3 – 6 , magnetic 7 , 8 and superconducting phases 4 – 6 . The electronic bands of this system were predicted 1 , 2 to narrow markedly 9 , 10 near the magic angle, leading to a variety of possible symmetry-breaking ground states 11 – 17 . Here, using measurements of the local electronic compressibility, we show that these correlated phases originate from a high-energy state with… Expand
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#### References

SHOWING 1-10 OF 66 REFERENCES
Charge smoothening and band flattening due to Hartree corrections in twisted bilayer graphene
• Physics, Materials Science
• Physical Review B
• 2019
Doping twisted bilayer graphene away from charge neutrality leads to an enormous buildup of charge inhomogeneities within each Moire unit cell. Here we show, using unbiased real-space self-consistentExpand
Electronic band structure and pinning of Fermi energy to Van Hove singularities in twisted bilayer graphene: A self-consistent approach
• Physics
• Physical Review B
• 2019
The emergence of flat bands in twisted bilayer graphene leads to an enhancement of interaction effects, and thus to insulating and superconducting phases at low temperatures, even though the exactExpand
Strong Coupling Phases of Partially Filled Twisted Bilayer Graphene Narrow Bands.
• Materials Science, Physics
• Physical review letters
• 2019
This work identifies states favored by Coulomb interactions projected onto the Wannier basis of the four narrow bands of the "magic angle" twisted bilayer graphene, and finds extended excited states, the gap to which decreases in the magnetic field. Expand
Phase diagram for the ν=0 quantum Hall state in monolayer graphene
The $\nu=0$ quantum Hall state in a defect-free graphene sample is studied within the framework of quantum Hall ferromagnetism. We perform a systematic analysis of the pseudospin anisotropies, whichExpand
Imaging of localized electronic states in the quantum Hall regime
• Chemistry, Medicine
• Nature
• 2000
This work searches for localized potential signals, at numerous locations, that oscillate with changing electron density, using a scanning electrometer probe and observes objects that interact, and at times form a lattice-like arrangement. Expand
One-Dimensional Electrical Contact to a Two-Dimensional Material
In graphene heterostructures, the edge-contact geometry provides new design possibilities for multilayered structures of complimentary 2D materials, and enables high electronic performance, including low-temperature ballistic transport over distances longer than 15 micrometers, and room-tem temperature mobility comparable to the theoretical phonon-scattering limit. Expand
Measurement of the quantum capacitance of interacting electrons in carbon nanotubes
• Physics
• 2006
The electronic capacitance of a one-dimensional system such as a carbon nanotube is a thermodynamic quantity that contains fundamental information about the ground state1. It is composed of anExpand
Nematic topological semimetal and insulator in magic-angle bilayer graphene at charge neutrality
• Physics
• Physical Review Research
• 2021
We report on a fully self-consistent Hartree-Fock calculation of interaction effects on the Moire flat bands of twisted bilayer graphene, assuming that valley U(1) symmetry is respected. We useExpand
Ferromagnetism in Narrow Bands of Moiré Superlattices.
• Physics, Medicine
• Physical review letters
• 2020
An intuitive picture based on extended Wannier orbitals is given, and the role of the quantum geometry of the band is emphasized, whose microscopic details may enhance or weaken ferromagnetism in moiré materials. Expand
Mapping the twist-angle disorder and Landau levels in magic-angle graphene
The importance of θ disorder as an unconventional type of disorder enabling the use of twist-angle gradients for bandstructure engineering, for realization of correlated phenomena and for gate-tunable built-in planar electric fields for device applications is established. Expand