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Related papers: The Mott-semiconducting state in the magic angle b…

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We analyze the phase diagram of twisted graphene bilayers near a magic angle. We consider the effect of the long range Coulomb interaction, treated within the self consistent Hartree-Fock approximation, and we study arbitrary band fillings.…

Strongly Correlated Electrons · Physics 2020-07-15 Tommaso Cea , Francisco Guinea

We investigate magnetic instabilities in charge-neutral twisted bilayer graphene close to so-called "magic angles" using a combination of real-space Hartree-Fock and dynamical mean-field theories. In view of the large size of the unit cell…

Strongly Correlated Electrons · Physics 2021-12-08 Javad Vahedi , Robert Peters , Ahmed Missaoui , Andreas Honecker , Guy Trambly de Laissardière

Twisted bilayer graphene (TBG) develops large moir\'e patterns at small twist angles with flat energy bands hosting domes of superconductivity. The large system size and intricate band structure have however hampered investigations into the…

Superconductivity · Physics 2022-07-19 Tomas Löthman , Johann Schmidt , Fariborz Parhizgar , Annica M. Black-Schaffer

Extensive investigations on the Moir\'e magic-angle have been conducted in twisted bilayer graphene, unlocking the mystery of unconventional superconductivity and insulating states. In analog to magic angle, here we demonstrate the new…

Mesoscale and Nanoscale Physics · Physics 2024-07-24 Qingxiang Ji , Bohan Li , Johan Christensen , Changguo Wang , Muamer Kadic

Recent experiments [arXiv: 1808.07865] on twisted bilayer graphene (TBLG) show that under hydrostatic pressure, an insulating state at quarter-filling of the moir\'e superlattice (i.e., one charge per supercell) emerges, in sharp contrast…

Strongly Correlated Electrons · Physics 2019-05-29 Bikash Padhi , Philip Phillips

Strong Coulomb repulsion is predicted to open a many-body charge gap at the Dirac point of graphene, transforming the semimetal into a Mott insulator. However, this correlated insulating phase has remained inaccessible in pristine graphene,…

Graphene-based moir\'e superlattice featuring flat bands is a promising platform for studying strongly correlated states. By tuning two twist angles and displacement fields in twisted mono-mono-bilayer graphene (TMMBG), we observed a…

Mesoscale and Nanoscale Physics · Physics 2024-07-01 Jin Jiang , Kenji Watanabe , Takashi Taniguchi , Mitali Banerjee

This work theoretically analyzes electronic ordering in AA-stacked bilayer graphene and the role of the Coulomb interaction in these many-body phenomena. Using the random phase approximation to account for screening, we find intra-layer…

Superconductivity · Physics 2024-10-15 A. O. Sboychakov , A. L. Rakhmanov , A. V. Rozhkov

When twisted to angles near 1{\deg}, graphene multilayers provide a new window on electron correlation physics by hosting gate-tuneable strongly-correlated states, including insulators, superconductors, and unusual magnets. Here we report…

We present a theory of competing ferromagnetic and superconducting orders in twisted double bilayer graphene (TDBG). In our theory, ferromagnetism is induced by Coulomb repulsion, while superconductivity with intervalley equal-spin pairing…

Strongly Correlated Electrons · Physics 2020-05-01 Fengcheng Wu , Sankar Das Sarma

Bilayer graphene twisted at the angle of about 1.1{\deg} better known as magic angle, exhibits ultra-flat moir\'e superlattice bands that are a source of highly-tunable, exotic quantum phenomena. Such phenomena, like superconductivity,…

Strongly Correlated Electrons · Physics 2024-11-05 Giovanna Feraco , Wissem Boubaker , Petra Rudolf , Antonija Grubišić-Čabo

Recently, magic-angle twisted bilayer graphene (MATBLG) has shown the emergence of various interaction-driven novel quantum phases at the commensurate fillings of the moir'e superlattice, while the charge neutrality point (CNP) remains…

Mesoscale and Nanoscale Physics · Physics 2022-11-07 Ayan Ghosh , Souvik Chakraborty , Unmesh Ghorai , Arup Kumar Paul , K. Watanabe , T. Taniguchi , Rajdeep Sensarma , Anindya Das

Strongly interacting electrons in solid-state systems often display tendency towards multiple broken symmetries in the ground state. The complex interplay between different order parameters can give rise to a rich phase diagram. Here, we…

Both insulating and conducting electronic behaviors have been experimentally seen in clean bilayer graphene samples at low temperature, and there is still no consensus on the nature of the interacting ground state at half-filling and in the…

Strongly Correlated Electrons · Physics 2019-09-11 Jia Ning Leaw , Ho-Kin Tang , Pinaki Sengupta , Fakher F. Assaad , Igor F. Herbut , Shaffique Adam

Even as the understanding of the mechanism behind correlated insulating states in magic-angle twisted bilayer graphene converges towards various kinds of spontaneous symmetry breaking, the metallic "normal state" above the insulating…

Strongly Correlated Electrons · Physics 2021-12-24 Peter Cha , Aavishkar A. Patel , Eun-Ah Kim

Motivated by recent experimental studies that have found signatures of a correlated insulator phase and tuning superconductivity in twisted bilayer graphene, we study the temperature-dependent conductivity, the spin correlation and the…

Strongly Correlated Electrons · Physics 2020-04-22 Wanying Chen , Yonghuan Chu , Tongyun Huang , Tianxing Ma

We study the possibility of charge order at quarter filling and antiferromagnetism at half-filling in a tight-binding model of magic angle twisted bilayer graphene. We build on the model proposed by Kang and Vafek [Physical Review X 8(3),…

Strongly Correlated Electrons · Physics 2021-12-07 B. Pahlevanzadeh , P. Sahebsara , D. Sénéchal

The discovery of magic-angle twisted trilayer graphene (tTLG) adds a new twist to the family of graphene moir\'e. The additional graphene layer unlocks a series of intriguing properties in the superconducting phase, such as the violation of…

Mesoscale and Nanoscale Physics · Physics 2024-01-05 Xiaoxue Liu , Naiyuan James Zhang , K. Watanabe , T. Taniguchi , J. I. A. Li

We investigate the correlated electrons in the magic-angle twisted bilayer graphene by using the slave-rotor mean-field theory. Owing to the extended figure of Wannier orbitals, we study the two-orbital cluster Hubbard model with…

Strongly Correlated Electrons · Physics 2020-07-01 Shin-Ming Huang , Yi-Ping Huang , Ting-Kuo Lee

Magic-angle twisted bilayer graphene is the best studied physical platform featuring moire potential induced narrow bands with non-trivial topology and strong electronic correlations. Despite their significance, the Chern insulating states…

Mesoscale and Nanoscale Physics · Physics 2024-06-11 Xiaoyu Wang , Oskar Vafek