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The effects of the long range electrostatic interaction in twisted bilayer graphene are described using the Hartree-Fock approximation. The results show a significant dependence of the band widths and shapes on electron filling, and the…

Mesoscale and Nanoscale Physics · Physics 2022-07-29 Tommaso Cea , Pierre A. Pantaleón , Niels R. Walet , Francisco Guinea

The occurrence of superconducting and insulating phases is well-established in twisted graphene bilayers, and they have also been reported in other arrangements of graphene layers. We investigate three such arrangements: untwisted AB…

Strongly Correlated Electrons · Physics 2021-08-11 Pierre A. Pantaleon , Tommaso Cea , Rory Brown , Niels R. Walet , Francisco Guinea

Twisted bilayer graphene near the magic angle is known to have a cascade of insulating phases at integer filling factors of the low-energy bands. In this Letter we address the nature of these phases through an unrestricted, large-scale…

Strongly Correlated Electrons · Physics 2024-09-30 Khagendra Adhikari , Kangjun Seo , K. S. D. Beach , Bruno Uchoa

We implement a self-consistent Hartree-Fock approximation based on a microscopic model in real space, which allows us to consider the interplay between the Hubbard and the extended Coulomb interaction in twisted bilayer graphene at the…

Mesoscale and Nanoscale Physics · Physics 2021-09-15 J. Gonzalez , T. Stauber

We study the symmetries of twisted trilayer graphene's band structure under various extrinsic perturbations, and analyze the role of long-range electron-electron interactions near the first magic angle. The electronic structure is modified…

Mesoscale and Nanoscale Physics · Physics 2021-10-04 Vo Tien Phong , Pierre A. Pantaleón , Tommaso Cea , Francisco Guinea

The polarizability of twisted bilayer graphene, due to the combined effect of electron-hole pairs, plasmons, and acoustic phonons is analyzed. The screened Coulomb interaction allows for the for- mation of Cooper pairs and superconductivity…

Strongly Correlated Electrons · Physics 2021-08-12 Tommaso Cea , Francisco Guinea

By applying a self-consistent Hartree-Fock approximation, we show that the mechanism of dynamical symmetry breaking can account for the insulating phase that develops about the charge neutrality point of twisted bilayer graphene around the…

Mesoscale and Nanoscale Physics · Physics 2020-09-02 J. Gonzalez , T. Stauber

The physics of non-local exchange interactions in graphene sheets is studied within a $\pi$-orbital tight-binding model using a Hartree-Fock approximation and Coulomb interactions modified at short distances by lattice effects and at large…

Mesoscale and Nanoscale Physics · Physics 2011-09-01 Jeil Jung , Allan H. MacDonald

We report on our studies of interacting electrons in bilayer graphene in a magnetic field. We demonstrate that the long range Coulomb interactions between electrons in this material are highly important and account for the band asymmetry in…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 D. S. L. Abergel , Tapash Chakraborty

We identify states favored by Coulomb interactions projected onto the Wannier basis of the four narrow bands of the "magic angle" twisted bilayer graphene. At the filling of two electrons/holes per moire unit cell, such interactions favor…

Strongly Correlated Electrons · Physics 2019-06-20 Jian Kang , Oskar Vafek

We analyze the effects of the long-range Coulomb interaction on the distribution of Berry curvature among the bands near charge neutrality of twisted bilayer graphene (TBG) closely aligned with hexagonal boron nitride (hBN). Due to the…

Mesoscale and Nanoscale Physics · Physics 2022-10-04 Pierre A. Pantaleón , Vo Tien Phong , Gerardo G. Naumis , Francisco Guinea

The effect of the intersite and interplane Coulomb interactions between the Dirac fermions on the formation of the Kohn-Luttinger superconductivity in bilayer doped graphene is studied disregarding the effects of the van der Waals potential…

Superconductivity · Physics 2016-02-08 M. Yu. Kagan , V. A. Mitskan , M. M. Korovushkin

Moir\'e superlattice in twisted bilayer graphene has been proven to be a versatile platform for exploring exotic quantum phases. Extensive investigations have been invoked focusing on the zero-magnetic-field phase diagram at the magic twist…

We study the effects of long and short-range electron-electron interactions in a graphene bilayer. Using a variational wavefunction technique we show that in the presence of long-range Coulomb interactions the clean bilayer is always…

Strongly Correlated Electrons · Physics 2009-11-11 Johan Nilsson , A. H. Castro Neto , N. M. R. Peres , F. Guinea

We theoretically study the effects of electron-electron interaction in twisted bilayer graphene in applied transverse dc electric field. When the twist angle is not very small, the electronic spectrum of the bilayer consists of four Dirac…

Strongly Correlated Electrons · Physics 2018-07-04 A. O. Sboychakov , A. V. Rozhkov , A. L. Rakhmanov , Franco Nori

Inter-Landau-level transitions in the bilayer graphene at high perpendicular magnetic field at the filling-factor v<<1 have been studied. The next-nearest-neighbor transitions, energy difference between dimer and non-dimer sites and layer…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 V. E. Bisti , N. N. Kirova

We report on our studies of interacting electrons in bilayer graphene in a magnetic field. We demonstrate that the long range Coulomb interactions between electrons in this material are highly important. We show that in the unbiased bilayer…

Mesoscale and Nanoscale Physics · Physics 2008-10-02 D. S. L. Abergel , Tapash Chakraborty

The non-interacting energy spectrum of graphene and its bilayer counterpart consists of multiple degeneracies owing to the inherent spin, valley and layer symmetries. Interactions among charge carriers are expected to spontaneously break…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 R. Thomas Weitz , Monica T. Allen , Benjamin E. Feldman , Jens Martin , Amir Yacoby

On a lattice model, we study the possibility of existence of gapped broken inversion symmetry phase (GBISP) of electrons with long-range Coulomb interaction in bilayer graphene using both self-consistent Hartree-Fock approximation (SCHFA)…

Strongly Correlated Electrons · Physics 2012-09-26 Xin-Zhong Yan , C. S. Ting

The tight-binding model is closely associated with the modified layer-based random-phase approximation to thoroughly investigate the electron-electron interactions in sliding bilayer graphene. The Coulomb interactions and intralayer and…

Mesoscale and Nanoscale Physics · Physics 2023-03-13 Chiun-Yan Lin , Ming-Fa Lin
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