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Valleytronics is a pioneering technological field relying on the valley degree of freedom to achieve novel electronic functionalities. Topological valley-polarized electrons confined to domain walls in bilayer graphene were extensively…

Materials Science · Physics 2020-10-09 Doried Ghader

For the unconventional superconducting phases in moire materials, a critical question is the role played by electronic interactions in the formation of Cooper pairs. In twisted bilayer graphene (tBLG), the strength of electronic…

Moir\'e superlattices created by the twisted stacking of two-dimensional crystalline monolayers can host electronic bands with flat energy dispersion in which interaction among electrons is strongly enhanced. These superlattices can also…

Mesoscale and Nanoscale Physics · Physics 2021-05-18 Xiaomeng Liu , Cheng-Li Chiu , Jong Yeon Lee , Gelareh Farahi , Kenji Watanabe , Takashi Taniguchi , Ashvin Vishwanath , Ali Yazdani

We investigate twisted double bilayer graphene (TDBG), a four-layer system composed of two AB-stacked graphene bilayers rotated with respect to each other by a small angle. Our ab initio band structure calculations reveal a considerable…

Mesoscale and Nanoscale Physics · Physics 2020-04-22 Fatemeh Haddadi , QuanSheng Wu , Alex J. Kruchkov , Oleg V. Yazyev

Topological magnons, quantized spin waves featuring nontrivial boundary modes, present a promising route toward lossless information processing. Realizing practical devices typically requires magnons excited in a controlled manner to enable…

Mesoscale and Nanoscale Physics · Physics 2026-05-26 Xueqing Wan , Quanchao Du , Jinlian Lu , Zhenlong Zhang , Jinyang Ni , Lei Zhang , Zhijun Jiang , Laurent Bellaiche

We compute the phase diagram of twisted bilayer graphene near the magic angle where the occurrence of flat bands enhances the effects of electron-electron interactions and thus unleashes strongly-correlated phenomena. Most importantly, we…

Strongly Correlated Electrons · Physics 2018-12-26 Dante M. Kennes , Johannes Lischner , Christoph Karrasch

Twisted bilayer materials have attracted tremendous attention due to their unique and novel properties. Here, we derive a thermodynamic model for twisted bilayer graphene (tBLG) within the framework of the classical statistical mechanics,…

Mesoscale and Nanoscale Physics · Physics 2021-11-09 Weidong Yan , Langquan Shui , Wengen Ouyang , Ze Liu

Twisted transition metal dichalcogenides (tTMDs) provide a highly tunable platform to explore the interplay between strong correlation and topology. Among them, the properties involving the charge degree of freedom have been extensively…

Strongly Correlated Electrons · Physics 2025-08-25 Wei-Tao Zhou , Zhao-Yang Dong , Zhao-Long Gu , Jian-Xin Li

Twisted bilayer graphene (TBG) is a recently discovered two-dimensional superlattice structure which exhibits strongly-correlated quantum many-body physics, including strange metallic behavior and unconventional superconductivity. Most of…

Mesoscale and Nanoscale Physics · Physics 2024-04-22 Cunyuan Jiang , Matteo Baggioli , Qing-Dong Jiang

We study the electron-phonon coupling in twisted bilayer graphene (TBG), which was recently experimentally observed to exhibit superconductivity around the magic twist angle $\theta\approx 1.05^\circ$. We show that phonon-mediated electron…

Mesoscale and Nanoscale Physics · Physics 2019-07-03 Biao Lian , Zhijun Wang , B. Andrei Bernevig

In this work we address the re-entrance of magic-angle phenomena (band flatness and quantum-geometric transport) in twisted bilayer graphene (TBG) subjected to strong magnetic fluxes $\pm \Phi_0$, $\pm 2 \Phi_0$, $\pm 3 \Phi_0$... ($\Phi_0…

Mesoscale and Nanoscale Physics · Physics 2022-10-04 Yifei Guan , Oleg V. Yazyev , Alexander Kruchkov

Moire superlattices in twisted bilayer graphene (TBG) and its derived structures can host exotic correlated quantum phenomena because the narrow moire flat minibands in those systems effectively enhance the electron-electron interaction.…

Materials Science · Physics 2021-10-18 Qiaoling Xu , Yuzheng Guo , Lede Xian

We demonstrate that low-lying triplon excitations in a bilayer Heisenberg antiferromagnet provide a promising avenue to realize magnetic analogs of twisted superfluid and supersolid phases that were recently reported for two-component…

Strongly Correlated Electrons · Physics 2021-09-08 Dhiman Bhowmick , Abhinava Chatterjee , Prasanta K. Panigrahi , Pinaki Sengupta

We propose that the electronic structure of twisted bilayer graphene (TBG) can be understood as Dirac fermions coupled with opposite pseudo magnetic fields generated by the moir\'e pattern. The two low-energy flat bands from each monolayer…

Mesoscale and Nanoscale Physics · Physics 2019-04-24 Jianpeng Liu , Junwei Liu , Xi Dai

The emergence of twistronics provides an unprecedented platform to modulate the band structure, resulting in exotic electronic phenomena ranging from ferromagnetism to superconductivity. However, such concept on phonon engineering is still…

Mesoscale and Nanoscale Physics · Physics 2020-08-25 Yufeng Zhang , Meng An , Dongxing Song , Haidong Wang , Weigang Ma , Xing Zhang

Recently, signatures of quantum anomalous Hall states with spontaneous ferromagnetism were observed in twisted bilayer graphenes (TBGs) near 3/4 filling [1, 2]. Importantly, it was demon-strated that an extremely small current can switch…

Mesoscale and Nanoscale Physics · Physics 2020-04-06 Wen-Yu He , David Goldhaber-Gordon , K. T. Law

Motivated by recent observation of the quantum spin Hall effect in monolayer germanene and twisted bilayer transition-metal-dichalcogenides (TMDs), we study the topological phases of moir\'e twisted bilayers with time-reversal symmetry and…

Mesoscale and Nanoscale Physics · Physics 2024-05-24 Yi-Ming Wu , Daniel Shaffer , Zhengzhi Wu , Luiz H. Santos

Magic-angle twisted bilayer graphene (TBG) with its flat bands provides a rich platform for exploring emergent electronic orders. Similarly, periodically buckled monolayer graphene has been proposed as a tunable alternative for realizing…

Mesoscale and Nanoscale Physics · Physics 2025-10-16 Jannes van Poppelen , Annica M. Black-Schaffer

Ferromagnetic honeycomb systems are known to exhibit a magnonic topological phase under the existence of the next-nearest neighbor Dzyaloshinskii-Moriya interaction (DMI). Motivated by the recent progress in the sublattice-specific control…

Mesoscale and Nanoscale Physics · Physics 2022-10-12 Hongsoek Kim , Se Kwon Kim

Flat electronic bands, characteristic of magic-angle twisted bilayer graphene (TBG), host a wealth of correlated phenomena. Early theoretical considerations suggested that, at the magic angle, the Dirac velocity vanishes and the entire…