Band structure and superconductivity in twisted trilayer graphene
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TLDR
In this article, the role of long-range electron-electron interactions near the first magic angle was analyzed in the band structure of twisted trilayer graphene, and superconducting phases with either spin-singlet/valley-triplet or spin-triplets/valleyssinglet symmetry were found with critical temperatures up to a few Kelvin.Abstract:
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 by these interactions in a similar way to twisted bilayer graphene. We analyze electron pairing due to long-wavelength charge fluctuations, which are coupled among themselves via the Coulomb interaction and additionally mediated by longitudinal acoustic phonons. We find superconducting phases with either spin-singlet/valley-triplet or spin-triplet/valley-singlet symmetry, with critical temperatures up to a few Kelvin for realistic choices of parameters.read more
Citations
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Evidence for unconventional superconductivity in twisted trilayer graphene
Hyun-Jin Kim,Youngjoon Choi,Cyprian Lewandowski,Alex Thomson,Yiran Zhang,Robert Polski,Kenji Watanabe,Takashi Taniguchi,Jason Alicea,Stevan Nadj-Perge +9 more
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Superconductivity from repulsive interactions in rhombohedral trilayer graphene: A Kohn-Luttinger-like mechanism
TL;DR: In this paper , the emergence of superconductivity in rhombohedral trilayer graphene due purely to the long-range Coulomb repulsion was studied, and it was shown that the order parameter shows a significant modulation within each valley pocket of the Fermi surface.
Posted Content
Superconductivity from Repulsive Interactions in Rhombohedral Trilayer Graphene: a Kohn-Luttinger-Like Mechanism.
TL;DR: In this paper, the emergence of superconductivity in rhombohedral trilayer graphene due purely to the long-range Coulomb repulsion was studied, and it was shown that the order parameter shows a significant modulation within each valley pocket of the Fermi surface.
Journal ArticleDOI
Nonlinear anomalous Hall effects probe topological phase-transitions in twisted double bilayer graphene
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TL;DR: In this paper , the authors investigate the second-order NLA Hall effects in the twisted double bilayer graphene (TDBG) and show that the whole family of NLA hall responses undergo a sign reversal across a topological phase transition.
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Engineering Proximity Exchange by Twisting: Reversal of Ferromagnetic and Emergence of Antiferromagnetic Dirac Bands in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mtext>Graphene/</mml:mtext><mml:msub><mml:mrow><mml:mi>Cr</mml:mi></mml:mrow><mml:mrow><mm
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TL;DR: In this article , the authors investigate the twist-angle and gate dependence of the proximity exchange coupling in twisted graphene on monolayer Cr 2 Ge 2 Te 6 bilayers from first principles.
References
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Unconventional superconductivity in magic-angle graphene superlattices
Yuan Cao,Valla Fatemi,Shiang Fang,Kenji Watanabe,Takashi Taniguchi,Efthimios Kaxiras,Pablo Jarillo-Herrero +6 more
TL;DR: 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.
Journal ArticleDOI
Correlated insulator behaviour at half-filling in magic-angle graphene superlattices
Yuan Cao,Valla Fatemi,Ahmet Demir,Shiang Fang,Spencer Tomarken,Jason Luo,Javier Sanchez-Yamagishi,Kenji Watanabe,Takashi Taniguchi,Efthimios Kaxiras,Raymond Ashoori,Pablo Jarillo-Herrero +11 more
TL;DR: 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.
Journal ArticleDOI
Moiré bands in twisted double-layer graphene
TL;DR: This work addresses the electronic structure of a twisted two-layer graphene system, showing that in its continuum Dirac model the moiré pattern periodicity leads to moirÉ Bloch bands.
Journal Article
Correlated Insulator Behaviour at Half-Filling in Magic Angle Graphene Superlattices
Yuan Cao,Valla Fatemi,Ahmet Demir,Shiang Fang,Spencer Tomarken,Jason Luo,Javier Sanchez-Yamagishi,Kenji Watanabe,Takashi Taniguchi,Efthimios Kaxiras,Raymond Ashoori,Pablo Jarillo-Herrero +11 more
TL;DR: In this article, the effects of the twist angle between different layers in a van der Waals heterostructure have been investigated and it was shown 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.
Journal ArticleDOI
Tuning superconductivity in twisted bilayer graphene.
Matthew Yankowitz,Shaowen Chen,Hryhoriy Polshyn,Yuxuan Zhang,Kenji Watanabe,Takashi Taniguchi,David Graf,Andrea Young,Cory Dean +8 more
TL;DR: This study demonstrates twisted bilayer graphene to be a distinctively tunable platform for exploring correlated states by inducing superconductivity at a twist angle larger than 1.1°—in which correlated phases are otherwise absent—by varying the interlayer spacing with hydrostatic pressure.