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It was recently suggested that the topology of magic-angle twisted bilayer graphene's (MATBG) flat bands could provide a novel mechanism for superconductivity distinct from both weakly-coupled BCS theory and the $d$-wave phenomenology of…

Strongly Correlated Electrons · Physics 2022-07-27 Shubhayu Chatterjee , Matteo Ippoliti , Michael P. Zaletel

We theoretically study the effect of magnetic moir\'e superlattice on the topological surface states by introducing a continuum model of Dirac electrons with a single Dirac cone moving in the time-reversal symmetry breaking periodic…

Mesoscale and Nanoscale Physics · Physics 2022-07-15 Zhaochen Liu , Huan Wang , Jing Wang

Electronic flat bands in momentum space, arising from strong localization of electrons in real space, are an ideal stage to realize strong correlation phenomena. In certain lattices with built-in geometrical frustration, electronic…

Two dimensional materials subject to long-wavelength modulations have emerged as novel platforms to study topological and correlated quantum phases. In this article, we develop a versatile and computationally inexpensive method to predict…

Mesoscale and Nanoscale Physics · Physics 2025-02-03 Valentin Crépel , Jennifer Cano

In this work, we propose a new and simple model that supports Chern semimetals. These new gapless topological phases share several properties with the Chern insulators like a well-defined Chern number associated to each band, topologically…

Mesoscale and Nanoscale Physics · Physics 2015-12-09 Giandomenico Palumbo , Konstantinos Meichanetzidis

Rhombohedral multilayer graphene, with its flat electronic bands and concentrated Berry curvature, is a promising material for the realization of correlated topological phases of matter. When aligned to an adjacent hexagonal boron nitride…

Mesoscale and Nanoscale Physics · Physics 2025-09-16 Samuel H. Aronson , Tonghang Han , Zhengguang Lu , Yuxuan Yao , Kenji Watanabe , Takashi Taniguchi , Long Ju , Raymond C. Ashoori

We study the electronic structure and band topology of fully relaxed twisted multi-layer graphene (TMLG). Isolated flat bands emerge in TMLG with the number of layers [$M+N$ with $M$ the layer number of the bottom few-layer graphene (FLG)]…

Mesoscale and Nanoscale Physics · Physics 2021-09-22 Xianqing Lin , Haotian Zhu , Jun Ni

In bilayer graphene rotationally faulted to theta=1.1 degrees, interlayer tunneling and rotational misalignment conspire to create a pair of low energy flat band that have been found to host various correlated phenomena at partial filling.…

Mesoscale and Nanoscale Physics · Physics 2021-06-21 Yu Saito , Jingyuan Ge , Louk Rademaker , Kenji Watanabe , Takashi Taniguchi , Dmitry A. Abanin , Andrea F. Young

We demonstrate the realization of topological band structures by exploiting the intrinsic spin-orbit coupling of dipolar interactions in combination with broken time-reversal symmetry. The system is based on polar molecules trapped in a…

An accurate description of the low-energy electronic bands in twisted bilayer graphene (tBLG) is of great interest due to their relation to correlated electron phases, such as superconductivity and Mott-insulator behavior at half-filling.…

Mesoscale and Nanoscale Physics · Physics 2024-04-17 Daniel Bennett , Daniel T. Larson , Louis Sharma , Stephen Carr , Efthimios Kaxiras

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

We study the collective excitation modes of the Chern insulator states in magic-angle twisted bilayer graphene aligned with hexagonal boron nitride (TBG/BN) at odd integer fillings ($\nu$) of the flat bands. For the $1 \times 1$…

Mesoscale and Nanoscale Physics · Physics 2023-06-07 Xianqing Lin , Quan Zhou , Cheng Li , Jun Ni

We study the spin waves of the triangular skyrmion crystal that emerges in a two dimensional spin lattice model as a result of the competition between Heisenberg exchange, Dzyalonshinkii-Moriya interactions, Zeeman coupling and uniaxial…

Mesoscale and Nanoscale Physics · Physics 2016-05-04 A. Roldán-Molina , A. S. Nunez , J. Fernández-Rossier

Magic-angle twisted bilayer graphene (MA-TBG) exhibits intriguing quantum phase transitions triggered by enhanced electron-electron interactions when its flat-bands are partially filled. However, the phases themselves and their connection…

Mesoscale and Nanoscale Physics · Physics 2021-04-14 Shuang Wu , Zhenyuan Zhang , K. Watanabe , T. Taniguchi , Eva Y. Andrei

Twisted bilayer graphene (TBLG) subject to a sequence of commensurate external periodic potentials reveals the formation of moir\'{e} fractals (MF) that share striking similarities with the central place theory (CPT) of economic geography,…

Mesoscale and Nanoscale Physics · Physics 2024-03-12 Deepanshu Aggarwal , Rohit Narula , Sankalpa Ghosh

We develop a symmetry indicator framework to efficiently predict the topology of superlattice-induced minibands with spin-orbit coupling. Our algorithm requires input only from the parent material before the superlattice is applied. The…

Mesoscale and Nanoscale Physics · Physics 2026-04-10 M. Nabil Y. Lhachemi , Valentin Crépel , Jennifer Cano

We study the atomic and electronic structures of the commensurate double moir\'{e} superlattices in fully relaxed twisted bilayer graphene (TBG) nearly aligned with the hexagonal boron nitride (BN). The single-particle effective Hamiltonian…

Mesoscale and Nanoscale Physics · Physics 2020-07-31 Xianqing Lin , Jun Ni

The breaking of time-reversal symmetry is a crucial ingredient to topological bands. It can occur intrisically in materials with magnetic order, or be induced by external fields, such as magnetic fields in quantum Hall systems, or…

Mesoscale and Nanoscale Physics · Physics 2022-05-10 Utso Bhattacharya , Swati Chaudhary , Tobias Grass , Allan S. Johnson , Simon Wall , Maciej Lewenstein

Twisted graphene moire superlattice has been demonstrated as an exotic platform for investigating correlated states and nontrivial topology. Among the moire family, twisted double bilayer graphene (TDBG) is a tunable flat band system…

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