Abnormal conductivity in low-angle twisted bilayer graphene

Zhang, Shuai; Song, Aisheng; Chen, Lingxiu; Jiang, Chengxin; Chen, Chen; Gao, Lei; Hou, Yuanjun; Liu, Luqi; Ma, Tianbao; Wang, Haomin; Feng, Xi‐Qiao; Li, Qunyang

doi:10.1126/sciadv.abc5555

Cited by 69 publications

(64 citation statements)

References 33 publications

(67 reference statements)

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“…The atomic structure was optimized until all force components are smaller than 0.5 meV/atom and the electronic calculations were then performed. The atomic structure relax- ation obtained by this method is shown to be in good agreement with experiments [18,[65][66][67] as well as the results obtained by other (both quantum and semi-classical) methods [60,[68][69][70], except that the intralayer equilibrium C-C bond distance is slightly overestimated by ∼ 1% [64].…”

Section: Introductionsupporting

confidence: 78%

Electronic properties of twisted multilayer graphene

Nguyen,

Hoang,

Charlier

2022

Preprint

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Twisted bilayer graphene displays many fascinating properties that can be tuned by varying the relative angle (also called twist angle) between its monolayers. As a remarkable feature, both the electronic flat bands and the corresponding strong electron localization have been obtained at a specific "magic" angle (∼ 1.1 • ), leading to the observation of several strongly correlated electronic phenomena. Such a discovery has hence inspired the creation of a novel research field called twistronics, i.e., aiming to explore novel physical properties in vertically stacked 2D structures when tuning the twist angle between the related layers. In this paper, a comprehensive and systematic study related to the electronic properties of twisted multilayer graphene (TMG) is presented based on atomistic calculations. The dependence of both the global and the local electronic quantities on the twist angle and on the stacking configuration are analyzed, fully taking into account atomic reconstruction effects. Consequently, the correlation between structural and electronic properties are clarified, thereby highlighting the shared characteristics and differences between various TMG systems as well as providing a comprehensive and essential overview. On the basis of these investigations, possibilities to tune the electronic properties are discussed, allowing for further developments in the field of twistronics.

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Section: Introductionsupporting

confidence: 78%

Electronic properties of twisted multilayer graphene

Nguyen,

Hoang,

Charlier

2022

Preprint

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“…However, note that when the twist angle between layers was rather small (generally less than 1°), atomic reconstruction could take place and was expected to have a profound effect on the band structures of the twisted bilayers 190 – 193 . In this case, the continuously varying rigid-lattice moiré pattern transformed to discrete commensurate domains divided by narrow domain walls, which had also been recently observed in twisted TMD vdW bilayers 194 , 195 .…”

Section: Interlayer Exciton Transport In Tmd Vdw Heterostructuresmentioning

confidence: 99%

“…All these works indicate that the diffusion barrier introduced by the moiré potential could be modified to affect exciton migration by tuning the twist angle or stacking mode between the constituent monolayers, which offers a novel way to control the exciton transport behavior in potential excitonic devices. However, note that when the twist angle between layers was rather small (generally less than 1°), atomic reconstruction could take place and was expected to have a profound effect on the band structures of the twisted bilayers [190][191][192][193] . In this case, the continuously varying rigidlattice moiré pattern transformed to discrete commensurate domains divided by narrow domain walls, which had also been recently observed in twisted TMD vdW bilayers 194,195 .…”

Section: Interlayer Exciton Transport Under Moiré Potentialsmentioning

confidence: 99%

Interlayer exciton formation, relaxation, and transport in TMD van der Waals heterostructures

et al. 2021

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Van der Waals (vdW) heterostructures based on transition metal dichalcogenides (TMDs) generally possess a type-II band alignment that facilitates the formation of interlayer excitons between constituent monolayers. Manipulation of the interlayer excitons in TMD vdW heterostructures holds great promise for the development of excitonic integrated circuits that serve as the counterpart of electronic integrated circuits, which allows the photons and excitons to transform into each other and thus bridges optical communication and signal processing at the integrated circuit. As a consequence, numerous studies have been carried out to obtain deep insight into the physical properties of interlayer excitons, including revealing their ultrafast formation, long population recombination lifetimes, and intriguing spin-valley dynamics. These outstanding properties ensure interlayer excitons with good transport characteristics, and may pave the way for their potential applications in efficient excitonic devices based on TMD vdW heterostructures. At present, a systematic and comprehensive overview of interlayer exciton formation, relaxation, transport, and potential applications is still lacking. In this review, we give a comprehensive description and discussion of these frontier topics for interlayer excitons in TMD vdW heterostructures to provide valuable guidance for researchers in this field.

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“…This effect was reported for twisted bilayer graphene at "magic" stacking angles (    1 1 ), demonstrating intrinsic unconventional superconductivity, as well as renormalized vibrational and electronic structures [44,45]. Recent studies identified local atomic reconstruction up to a crossover angle of rigid twist at 5°, which results in abnormal electrical conductivity [46]. Our simulation results for a bilayer with     0 7 show that the moiré pattern selforganizes into a reconstructed triangular network by sacrificing the elastic deformation in graphene layers.…”

Section: Discussionmentioning

confidence: 71%

Robustness of structural superlubricity beyond rigid models

Feng

2022

Friction

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Structural superlubricity is a theoretical concept stating that the friction force is absent between two rigid, incommensurate crystalline surfaces. However, elasticity of the contact pairs could modify the lattice registry at interfaces by nucleating local slips, favoring commeasure. The validity of structural superlubricity is thus concerned for large-scale systems where the energy cost of elastic distortion to break the lattice registry is low. In this work, we study the size dependence of superlubricity between single-crystal graphite flakes. Molecular dynamics simulations show that with nucleation and propagation of out-of-plane dislocations and strained solitons at Bernal interfaces, the friction force is reduced by one order of magnitude. Elastic distortion is much weaker for non-Bernal or incommensurate ones, remaining notable only at the ends of contact. Lattice self-organization at small twist angles perturbs the state of structural superlubricity through a reconstructed potential energy surface. Theoretical models are developed to illustrate and predict the interfacial elastoplastic behaviors at length scales beyond those in the simulations. These results validate the rigid assumption for graphitic superlubricity systems at microscale, and reveal the intrinsic channels of mechanical energy dissipation. The understandings lay the ground for the design of structural superlubricity applications.

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Abnormal conductivity in low-angle twisted bilayer graphene

Cited by 69 publications

References 33 publications

Electronic properties of twisted multilayer graphene

Electronic properties of twisted multilayer graphene

Interlayer exciton formation, relaxation, and transport in TMD van der Waals heterostructures

Robustness of structural superlubricity beyond rigid models

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