Chiral $p$-wave superconductivity in twisted bilayer graphene from  dynamical mean field theory

Pahlevanzadeh, B.; Sahebsara, Peyman; Sénéchal, David

doi:10.21468/scipostphys.11.1.017

Cited by 10 publications

(11 citation statements)

References 35 publications

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“…This paper is an extension of our previous work [7] on the superconducting state of TBG. We will use the same premise: We will start from the tight-binding model proposed by Kang and Vafek [1], based on the microscopic analysis of Moon and Koshino [8].…”

Section: Introductionmentioning

confidence: 77%

“…1, borrowed from Ref. [7]. We will only retain the largest hopping integrals among those computed in Ref.…”

Section: The Low-energy Modelmentioning

confidence: 99%

“…However, instead of applying cluster dynamical mean field theory (CDMFT) as in Ref. [7], we will apply another cluster method, the variational cluster approximation (VCA), based on a 12-site cluster. In addition, we will include extended interactions, which were neglected in Ref.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, we will include extended interactions, which were neglected in Ref. [7] and will extend the VCA by a mean-field treatment of inter-cluster interactions. Since the model studied is nearly particle-hole symmetric, the conclusions reached at quarter filling also apply at three-quarter filling.…”

Section: Introductionmentioning

confidence: 99%

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Charge order and antiferromagnetism in twisted bilayer graphene from the variational cluster approximation

Pahlevanzadeh¹,

Sahebsara²,

Sénéchal³

2021

Preprint

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We study the possibility of charge order at quarter filling and antiferromagnetism at halffilling in a tight-binding model of magic angle twisted bilayer graphene. We build on the model proposed by Kang and Vafek [1], relevant to a twist angle of 1.30 • , and add on-site and extended density-density interactions. Applying the variational cluster approximation with an exact-diagonalization impurity solver, we find that the system is indeed a correlated (Mott) insulator at fillings 1 4 , 1 2 and 3 4 . At quarter filling, we check that the most probable charge orders do not arise, for all values of the interaction tested. At half-filling, antiferromagnetism only arises if the local repulsion U is sufficiently large compared to the extended interactions, beyond what is expected from the simplest model of extended interactions.

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Section: Introductionmentioning

confidence: 77%

“…1, borrowed from Ref. [7]. We will only retain the largest hopping integrals among those computed in Ref.…”

Section: The Low-energy Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Charge order and antiferromagnetism in twisted bilayer graphene from the variational cluster approximation

Pahlevanzadeh¹,

Sahebsara²,

Sénéchal³

2021

Preprint

Self Cite

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“…1, it reproduces the band structure well over a wide range of energies and not just the flat minibands close to the Fermi level. However, in the range of intermediate values of U/t where mainly the flat minibands contribute to the magnetism, effective low-energy models would have the advantage of being more amenable to numerical approaches [14,[67][68][69][70] such that we suggest the investigation of magnetism by such methods as a topic for further studies.…”

Section: Discussionmentioning

confidence: 99%

Magnetism of magic-angle twisted bilayer graphene

et al. 2021

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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 close to magic angles, we examine a previously proposed rescaling that permits to mimic the same underlying flat minibands at larger twist angles. We find that localized magnetic states emerge for values of the Coulomb interaction UU that are significantly smaller than what would be required to render an isolated layer antiferromagnetic. However, this effect is overestimated in the rescaled system, hinting at a complex interplay of flatness of the minibands close to the Fermi level and the spatial extent of the corresponding localized states. Our findings shed new light on perspectives for experimental realization of magnetic states in charge-neutral twisted bilayer graphene.

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