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We present a simple model that we believe captures the key aspects of the competition between superconducting and insulating states in twisted bilayer graphene. Within this model, the superconducting phase is primary, and arises at generic…

Strongly Correlated Electrons · Physics 2019-09-16 Yang-Zhi Chou , Yu-Ping Lin , Sankar Das Sarma , Rahul M. Nandkishore

We study the superconducting pairing symmetry in twisted bilayer graphene by solving the Bogoliubov-de Gennes equation for all electrons in moir\'{e} supercells. With increasing the pairing potential, the system evolves from the mixed…

Strongly Correlated Electrons · Physics 2018-11-05 Ying Su , Shi-Zeng Lin

In this work, we propose a mechanism of inducing stable nodal superconductivity for multiple-flat-band systems. This mechanism is based on the degenerate flat band nature, so that not only intra-eigen-band pairing, but also inter-eigen-band…

Superconductivity · Physics 2025-01-23 Chao-Xing Liu , B. Andrei Bernevig

We analyze an analog of the $t$-$J$-$U$ model as applied to the description of a single moir\'e flat band of twisted WSe$_2$ bilayer. To take into account the correlation effects induced by a significant strength of the Coulomb repulsion,…

Strongly Correlated Electrons · Physics 2025-05-15 M. Zegrodnik , A. Biborski

We report on the energy spectrum of electrons in twisted bilayer graphene (tBLG) obtained by the band-unfolding method in the tight-binding model. We find the band-gap opening at particular points in the reciprocal space, that elucidates…

Materials Science · Physics 2017-03-08 Hirofumi Nishi , Yu-ichiro Matsushita , Atsushi Oshiyama

The observation of flat energy bands in transition metal dichalcogenide bilayers such as twisted WSe${}_2$ makes those materials interesting prospects for reproducing the behavior observed in graphene-based systems. We use an effective…

Strongly Correlated Electrons · Physics 2022-12-21 Mathieu Bélanger , Jérôme Fournier , David Sénéchal

Strong evidence of unconventional superconductivity has been very recently reported experimentally in twisted transition metal dichalcogenide bilayer and gathered a significant amount of interest. Here we consider the Hubbard model on a…

Superconductivity · Physics 2025-10-29 Andrzej Biborski , Michał Zegrodnik

We review the theoretical modelling of moir\'e materials, focusing on various aspects of magic-angle twisted bilayer graphene (MA-TBG) viewed through the lens of Hartree-Fock mean-field theory. We first provide an elementary introduction to…

Strongly Correlated Electrons · Physics 2026-03-20 Yves H. Kwan , Ziwei Wang , Glenn Wagner , Nick Bultinck , Steven H. Simon , Siddharth A. Parameswaran

Multilayer moir\'e materials can exhibit topological electronic features yet are inherently quasiperiodic -- leading to wave function interference whose Anderson-localizing tendency can be mitigated by topology. We consider a quasiperiodic…

Mesoscale and Nanoscale Physics · Physics 2025-01-22 Xinghai Zhang , Justin H. Wilson , Matthew S. Foster

Two-dimensional moir\'e Chern bands provide an exceptional platform for exploring a variety of many-body quantum phases at zero magnetic field within a lattice system. One particular intriguing possibility is that flat Chern bands can, in…

We propose an SU(4) spin-valley-fermion model to investigate the superconducting instabilities of twisted bilayer graphene (TBG). In this approach, bosonic fluctuations associated with an emergent SU(4) symmetry, corresponding to combined…

Superconductivity · Physics 2021-01-20 Yuxuan Wang , Jian Kang , Rafael M. Fernandes

We show that the $e$-$e$ interaction induces a strong breakdown of valley symmetry for each spin channel in twisted trilayer graphene, leading to a ground state where the two spin projections have opposite sign of the valley symmetry…

Superconductivity · Physics 2023-08-02 J. Gonzalez , T. Stauber

We show how the pairing symmetry of superconducting states in twisted bilayer graphene can be experimentally identified by theoretically studying effects of externally applied in-plane magnetic field and strain. In the low field regime,…

Superconductivity · Physics 2019-07-03 Fengcheng Wu , Sankar Das Sarma

External magnetic fields conventionally suppress superconductivity, both by orbital and paramagnetic effects. A recent experiment has shown that in a Bernal stacked bilayer graphene system, the opposite occurs -- a finite critical magnetic…

Superconductivity · Physics 2023-08-01 Gal Shavit , Yuval Oreg

The effect of Coulomb interaction in an ensemble of Dirac fermions on the formation of superconducting pairing in monolayer and bilayer doped graphene is studied using the Kohn-Luttinger mechanism disregarding the Van der Waals potential of…

Superconductivity · Physics 2015-01-19 M. Yu. Kagan , V. A. Mitskan , M. M. Korovushkin

Two-dimensional (2D) moire systems based on twisted bilayer graphene and transition metal dichalcogenides provide a promising platform to investigate emergent phenomena driven by strong electron-electron interactions in partially-filled…

Materials Science · Physics 2023-11-28 Ya-Ning Ren , Hui-Ying Ren , Kenji Watanabe , Takashi Taniguchi , Lin He

Twisted bilayer graphene displays insulating and superconducting phases caused by exceptional flattening of its lowest energy bands. Superconductivity with highest $T_c$ appears at hole and electron dopings, near half-filling for valence or…

Superconductivity · Physics 2020-06-29 Dmitry V. Chichinadze , Laura Classen , Andrey V. Chubukov

We report on the theoretical electronic spectra of twisted phosphorene bilayers exhibiting moir\'e patterns, as computed by means of a continuous approximation to the moir\'e superlattice Hamiltonian. Our model is constructed by…

Mesoscale and Nanoscale Physics · Physics 2022-06-23 Isaac Soltero , Jonathan Guerrero-Sánchez , Francisco Mireles , David A. Ruiz-Tijerina

Motivated by experiments on rhombohedral tetralayer graphene showing signs of superconductivity emerging from a valley-polarized normal state, we here analyze theoretically how scanning tunneling spectroscopy can be used to probe the…

Superconductivity · Physics 2026-04-30 Denis Sedov , Mathias S. Scheurer

Motivated by the recently observed insulating states in twisted bilayer graphene, we study the nature of the correlated insulating phases of the twisted bilayer graphene at commensurate filling fractions. We use the continuum model and…

Strongly Correlated Electrons · Physics 2020-07-23 Yi Zhang , Kun Jiang , Ziqiang Wang , Fuchun Zhang