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We apply a generalized Schrieffer-Wolff transformation to the extended Anderson-like topological heavy fermion (THF) model for the magic-angle $(\theta=1.05^{\circ})$ twisted bilayer graphene (MATBLG) (Phys. Rev. Lett. 129, 047601 (2022)),…

Strongly Correlated Electrons · Physics 2023-07-26 Haoyu Hu , B. Andrei Bernevig , Alexei M. Tsvelik

Motivated by recent developments in twisted bilayer graphene moir\'e superlattices, we investigate the effects of electron-electron interactions in a honeycomb lattice with an applied periodic potential using a finite-temperature…

Mesoscale and Nanoscale Physics · Physics 2020-05-28 Robert E. Throckmorton , S. Das Sarma

Magic-angle twisted bilayer graphene has recently become a thriving material platform realizing correlated electron phenomena taking place within its topological flat bands. Several numerical and analytical methods have been applied to…

Strongly Correlated Electrons · Physics 2021-09-17 Bin-Bin Chen , Yuan Da Liao , Ziyu Chen , Oskar Vafek , Jian Kang , Wei Li , Zi Yang Meng

Topological heavy fermion models[1-5] describe the flat bands in magic-angle twisted bilayer graphene (MATBG) as arising from the hybridization between localized flat-band orbitals (f-electrons) and nearly-free conduction bands…

Mesoscale and Nanoscale Physics · Physics 2025-03-25 Zhenyuan Zhang , Shuang Wu , Dumitru Călugăru , Haoyu Hu , Takashi Taniguchi , Kenji Wanatabe , Andrei B. Bernevig , Eva Y. Andrei

Magic angle twisted bilayer graphene (MATBG) hosts narrow moir\'e bands with meV-scale energy splittings, making its correlated phases sensitive to both material parameters and modeling choices in low-energy downfolding. We develop an ab…

Strongly Correlated Electrons · Physics 2026-03-12 Raehyun Kim , Woochang Kim , Kevin D. Stubbs , Steven G. Louie , Lin Lin

We discuss the effect of long-range interactions within the self-consistent Hartree-Fock (HF) approximation in comparison to short-range atomic Hubbard interactions on the band structure of twisted bilayer graphene (TBG) at charge…

We characterize gap-opening mechanisms in the topological heavy fermion (THF) model of magic-angle twisted bilayer graphene (MATBG), with and without electron-phonon coupling, using dynamical mean-field theory (DMFT) with the numerical…

Strongly Correlated Electrons · Physics 2024-12-05 Seongyeon Youn , Beomjoon Goh , Geng-Dong Zhou , Zhi-Da Song , Seung-Sup B. Lee

The rich phenomenology of twisted bilayer graphene (TBG) near the magic angle is believed to arise from electron correlations in topological flat bands. An unbiased approach to this problem is highly desirable, but also particularly…

Strongly Correlated Electrons · Physics 2021-09-28 Johannes S. Hofmann , Eslam Khalaf , Ashvin Vishwanath , Erez Berg , Jong Yeon Lee

It has been recently postulated, that the strongly correlated flat bands of magicangle twisted bilayer graphene (MATBG) can host coexisting heavy and light carriers. While transport and spectroscopic measurements have shown hints of this…

We consider a lattice model of twisted bilayer graphene (TBG) for incommensurate twist angles, focusing on the role of large-momentum-transfer Umklapp terms. These terms, which nearly connect the Fermi points of different layers, are…

Strongly Correlated Electrons · Physics 2026-03-31 Ian Jauslin , Vieri Mastropietro

A perturbative renormalization group (RG) scheme for light-front Hamiltonian is formulated on the basis of the Bloch-Horowitz effective Hamiltonian, and applied to the simplest $\phi^4$ model with spontaneous breaking of the $Z_2$ symmetry.…

High Energy Physics - Theory · Physics 2009-10-28 Takanori Sugihara , Masanobu Yahiro

In this work, we study an interacting tight-binding model of magic-angle twisted bilayer graphene (MATBG), with a twist angle of $1.05^\circ$. We derive effective theories based on a mean-field normal state at charge neutrality, thereby…

Strongly Correlated Electrons · Physics 2025-05-27 Miguel Sánchez Sánchez , José González , Tobias Stauber

In twisted bilayer graphene (TBG), a twist-angle-dependent competition between interlayer stacking energy and intralayer elastic energy results in flat rigid layers at large twist angles and lattice reconstruction at small twist angles.…

Mesoscale and Nanoscale Physics · Physics 2023-03-29 Xiao-Feng Zhou , Yi-Wen Liu , Chen-Yue Hao , Chao Yan , Qi Zheng , Ya-Ning Ren , Ya-Xin Zhao , Kenji Watanabe , Takashi Taniguchi , Lin He

Twisted bilayer graphene (TBG) and other quasi-two-dimensional moir\'e superlattices have attracted significant attention due to the emergence of various correlated and topological states associated with the flat bands in these systems. In…

Mesoscale and Nanoscale Physics · Physics 2024-09-24 Xin Lu , Bo Xie , Yue Yang , Xiao Kong , Jun Li , Feng Ding , Zhu-Jun Wang , Jianpeng Liu

We show that the entire continuous model of twisted bilayer graphene (TBG) (and not just the two active bands) with particle-hole symmetry is anomalous and hence incompatible with a lattice model. Previous works, e.g., [Phys. Rev. Lett.…

Mesoscale and Nanoscale Physics · Physics 2022-04-29 Zhi-Da Song , Biao Lian , Nicolas Regnault , B. Andrei Bernevig

Magic-angle twisted bilayer graphene (MATBG) exhibits correlated phenomena such as superconductivity and Mott insulating state related to the weakly dispersing flat band near the Fermi energy. Beyond its moir\'e period, such flat band is…

The interplay between interlayer van der Waals interaction and intralayer lattice distortion can lead to structural reconstruction in slightly twisted bilayer graphene (TBG) with the twist angle being smaller than a characteristic angle…

Mesoscale and Nanoscale Physics · Physics 2020-07-07 Yi-Wen Liu , Ying Su , Xiao-Feng Zhou , Long-Jing Yin , Chao Yan , Si-Yu Li , Wei Yan , Sheng Han , Zhong-Qiu Fu , Yu Zhang , Qian Yang , Ya-Ning Ren , Lin He

We study the quantum many-body ground states of electrons on the half-filled honeycomb lattice with short- and long-ranged density-density interactions as a model for graphene. To this end, we employ the recently developed truncated-unity…

Strongly Correlated Electrons · Physics 2017-12-06 David Sánchez de la Peña , Julian Lichtenstein , Carsten Honerkamp , Michael M. Scherer

Twisted double bilayer graphene (tDBLG) is a moir\'e material that has recently generated significant interest because of the observation of correlated phases near the magic angle. We carry out atomistic Hartree theory calculations to study…

Overlaying two graphene layers with a small twist angle can create a moire superlattice to realize exotic phenomena that are entirely absent in graphene monolayer. A representative example is the predicted formation of localized…

Mesoscale and Nanoscale Physics · Physics 2024-03-08 Qi Zheng , Chen-Yue Hao , Xiao-Feng Zhou , Ya-Xin Zhao , Jia-Qi He , Lin He