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In disordered lattices, itinerant electrons typically undergo Anderson localization due to random phase interference, which suppresses their motion. By contrast, in flat-band systems where electrons are intrinsically localized owing to…

Mesoscale and Nanoscale Physics · Physics 2026-04-28 Zhe Hou , Hailong Li , Qing Yan , Yu-Hang Li , Hua Jiang

We report the observation of anomalously strong 2D band in twisted bilayer graphene (tBLG) with large rotation angles under 638-nm and 532-nm visible laser excitation. The 2D band of tBLG can reach four times as opposed to two times as…

The generalized tight-binding model is developed to investigate the magneto-electronic properties in twisted bilayer graphene system. All the interlayer and intralayer atomic interactions are included in the Moire superlattice. The twisted…

Mesoscale and Nanoscale Physics · Physics 2019-07-23 Chiun-Yan Lin , Ming-Fa Lin

We investigate magic-angle twisted bilayer graphene (MATBG) with proximity-induced Ising and Rashba spin-orbit couplings (SOC) in the top layer, as recently achieved experimentally. Utilizing the Bistritzer-MacDonald model with SOCs, we…

Mesoscale and Nanoscale Physics · Physics 2024-10-10 Yuting Tan , Yang-Zhi Chou , Fengcheng Wu , Sankar Das Sarma

The unexpected discovery of superconductivity and strong electron correlation in twisted bilayer graphene (TBG), a system containing only sp electrons, is considered as one of the most intriguing developments in two-dimensional materials in…

Mesoscale and Nanoscale Physics · Physics 2025-04-22 Wei-Chen Wang , Feng-Wu Chen , Kuan-Sen Lin , Justin T. Hou , Ho-Chun Lin , Mei-Yin Chou

The Hamiltonian of the magic-angle twisted symmetric trilayer graphene (TSTG) can be decomposed into a TBG-like flat band Hamiltonian and a high-velocity Dirac fermion Hamiltonian. We use Hartree-Fock mean field approach to study the…

Mesoscale and Nanoscale Physics · Physics 2021-10-19 Fang Xie , Nicolas Regnault , Dumitru Călugăru , B. Andrei Bernevig , Biao Lian

In twisted bilayer graphene (TBG) a moir\'e pattern forms that introduces a new length scale to the material. At the 'magic' twist angle of 1.1{\deg}, this causes a flat band to form, yielding emergent properties such as correlated…

Materials with flat electronic bands often exhibit exotic quantum phenomena owing to strong correlations. Remarkably, an isolated low-energy flat band can be induced in bilayer graphene by simply rotating the layers to 1.1$^{\circ}$,…

Mesoscale and Nanoscale Physics · Physics 2019-01-29 Matthew Yankowitz , Shaowen Chen , Hryhoriy Polshyn , K. Watanabe , T. Taniguchi , David Graf , Andrea F. Young , Cory R. Dean

A number of moir\'e graphene systems have nearly flat topological bands where electron motion is strongly correlated. Though microscopically these systems are only quasiperiodic, they can typically be treated as translation invariant to an…

Mesoscale and Nanoscale Physics · Physics 2021-03-10 Dan Mao , T. Senthil

We study the commensurately-tilted bilayer graphene in the tight-binding model with changing the interlayer distance, which can be tuned by pressure. We find that at the commensurately-tilted bilayer graphene with moderate rotating angles,…

Mesoscale and Nanoscale Physics · Physics 2021-03-24 Aya Yamada , Yasumasa Hasegawa

We have used ab initio density functional theory, incorporating van der Waals corrections, to study twisted bilayer graphene (TBLG) where Stone-Wales defects or monovacancies are introduced in one of the layers. We compare these results to…

Materials Science · Physics 2015-04-30 Kanchan Ulman , Shobhana Narasimhan

The symmetry-broken correlated states in twisted double bilayer graphene (TDBG) can be tuned via several external knobs, including twist angle, displacement field, and carrier density. However, a direct, momentum-resolved characterization…

We report the discovery of a series of non-equilibrium magic angles at which isolated topological flat quasienergy bands form in AA-stacked twisted multilayer graphene under circularly polarized light. These non-equilibrium magic angles can…

Strongly Correlated Electrons · Physics 2025-03-05 Yantao Li , Wang-Kong Tse

The low-energy bands of twisted bilayer graphene form Dirac cones with approximate electron-hole symmetry at small rotation angles. These crossings are protected by the emergent symmetries of moir\'e patterns, conferring a topological…

Mesoscale and Nanoscale Physics · Physics 2020-11-25 Hector Ochoa

The in-plane DC conductivity of twisted bilayer graphene (TBLG) is calculated using an expansion of the real-space Kubo-Bastin conductivity in terms of Chebyshev polynomials. We investigate within a tight-binding (TB) approach the transport…

Mesoscale and Nanoscale Physics · Physics 2018-03-28 M. Anđelković , L. Covaci , F. M. Peeters

Twisted bilayer graphene (TBG) exhibits fascinating correlation-driven phenomena like the superconductivity and Mott insulating state, with flat bands and a chiral lattice structure. We find by quantum transport calculations that the…

Mesoscale and Nanoscale Physics · Physics 2021-02-03 Yizhou Liu , Tobias Holder , Binghai Yan

The crystal structure of a material creates a periodic potential that electrons move through giving rise to the electronic band structure of the material. When two-dimensional materials are stacked, the twist angle between the layers…

Strongly Correlated Electrons · Physics 2020-07-07 Zhiming Zhang , Yimeng Wang , Kenji Watanabe , Takashi Taniguchi , Keiji Ueno , Emanuel Tutuc , Brian J. LeRoy

Twisted bilayer graphene (TBG) with interlayer twist angles near the magic angle $\approx 1.08^{\circ}$ hosts flat bands and exhibits correlated states including Mott-like insulators, superconductivity and magnetism. Here we report combined…

Strongly correlated states are commonly emerged in twisted bilayer graphene (TBG) with magic-angle, where the electron-electron (e-e) interaction U becomes prominent relative to the small bandwidth W of the nearly flat band. However, the…

Mesoscale and Nanoscale Physics · Physics 2023-07-11 Kaihui Li , Long-Jing Yin , Chenglong Che , Xueying Liu , Yulong Xiao , Songlong Liu , Qingjun Tong , Si-Yu Li , Anlian Pan

We study Dirac points of the chiral model of twisted bilayer graphene (TBG) with constant in-plane magnetic field. For a fixed small magnetic field, we show that as the angle of twisting varies between magic angles, the Dirac points move…

Mathematical Physics · Physics 2023-06-22 Simon Becker , Maciej Zworski