Alternating twisted multilayer graphene: generic partition rules, double flat bands, and orbital magnetoelectric effect

Xie, Bo; Peng, Ran; Zhang, Shi-Hao; Liu, Jianpeng

doi:10.1038/s41524-022-00789-5

Cited by 15 publications

(5 citation statements)

References 77 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This is not surprising, since in the viewpoint of band structure the twisted monolayer-trilayer graphene (denoted as A-ABA) is equivalent to the sum of a twisted monolayer-bilayer graphene and a monolayer graphene (i.e., A-AB+A). [40] Nevertheless, the additional 'equivalent monolayer' is more dispersive, making the electrons less correlated in the twisted monolayer-trilayer graphene than that of the twisted monolayer-bilayer graphene.…”

Section: Resultsmentioning

confidence: 99%

Tunable correlation in twisted monolayer–trilayer graphene

et al. 2023

View full text Add to dashboard Cite

Flat-band physics of Moiré superlattices, originally discovered in the celebrated twisted bilayer graphene, have recently been intensively explored in multilayer graphene systems that can be further controlled by electric field. In this work, we experimentally find the evidence of correlated insulators at half filling of the electron moiré band of twisted monolayer-trilayer graphene with a twist angle around 1.2 degrees. Van Hove singularity (VHS), manifested as enhanced resistance and zero Hall voltage, is observed to be distinct in conduction and valence flat bands. It also depends on the direction and magnitude of displacement fields, consistent with the asymmetric crystal structure. While the resistance ridges at VHS can be enhanced by magnetic fields, when they cross commensurate fillings of the moiré superlattice in the conduction band, the enhancement is so strong that signatures of correlated insulator appear, which may further develop into an energy gap depending on the correlation strength. At last, Fermi velocity derived from temperature coefficients of resistivity is compared between conduction and valence bands with different displacement fields. It is found that electronic correlation has a negative dependence on Fermi velocity, which in turn could be used to quantify the correlation strength.

show abstract

Section: Resultsmentioning

confidence: 99%

Tunable correlation in twisted monolayer–trilayer graphene

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Inspired by stacking two graphene at a speci c angle to present some unexpected properties, such as superconductor or insulator, 11,12 the interlayer twist endows a new degree of freedom to exibly engineer the electronic structures and interlayer excitons. 13 To date, arti cially twisted 2D semiconductor heterostructures are mainly focused on transition-metal dichalcogenides (TMDs), which can indirectly form interlayer excitons in two steps, namely, photoexcitation forming intralayer exciton and then the photogenerated electron or hole transfer into the opposite sublayers.…”

Section: Introductionmentioning

confidence: 99%

The interlayer twist effectively regulates interlayer excitons in InSe/Sb van der Waals heterostructure

Niu,

Shi,

Guan

et al. 2024

Preprint

View full text Add to dashboard Cite

The interlayer twist angle endows a new degree of freedom to manipulate the spatially separated interlayer excitons in van der Waals (vdWs) heterostructures. Herein, we find that the band-edge Γ-Γ interlayer excitation directly forms interlayer exciton in InSe/Sb heterostructure, different from that of transition metal dichalcogenides (TMDs) heterostructures in two-step processes by intralayer excitation and transfer. By tuning the interlayer coupling and breathing vibrational modes associated with the Γ-Γ photoexcitation, the interlayer twist can significantly adjust the excitation peak position and lifetime of recombination. The interlayer excitation peak in InSe/Sb heterostructure can shift ~ 400 meV, and the interlayer exciton lifetime varies in hundreds of nanoseconds as a periodic function of the twist angle (0°-60°). This work enriches the understanding of interlayer exciton formation and facilitates the artificial excitonic engineering of vdWs heterostructures.

show abstract

“…转角石墨烯的研究领域由魔角双层石墨烯体系开始, 向更多各种各样的莫尔石墨烯体系进发. 理论学家预测了在转角多层石墨烯体系和石墨烯-氮化硼莫尔异质结体系中均具有拓扑非平庸的平带 [46][47][48][49][50][51][52][53][54][55][56][57][58][59][60] . 这些拓扑平带普遍具有非零的谷陈数, 并且拓扑性质可以被垂直电场高度调控.…”

unclassified

“…如近期实验在转角双层-单层石墨烯体系中观测到轨道陈绝缘态 [61][62][63] 和零陈数的关联绝缘态 [61,64,65] ; 在转角双层-双层石墨烯体系中观测到自旋极化态 [66][67][68][69] 、向列序态 [70] 、广义维格纳晶格和奇异金属态 [71] 等新奇物态, 在交错转角三层石墨烯中则发现了平带和狄拉克锥共存的奇特电子结构 [72] 、违反泡利极限的非常规超导态 [73][74][75][76] 等新奇现象. 而在氮化硼-石墨烯-氮化硼莫尔异质结中观测到了关联绝缘态 [77] , 在氮化硼-三层石墨烯莫尔异质结中, 也观测到了关联绝缘态 [78] 和量子反常霍尔效应 [79] . 总而言之, 非平子结构特征 [55,80] .…”

unclassified

“…而在氮化硼-石墨烯-氮化硼莫尔异质结中观测到了关联绝缘态 [77] , 在氮化硼-三层石墨烯莫尔异质结中, 也观测到了关联绝缘态 [78] 和量子反常霍尔效应 [79] . 总而言之, 非平子结构特征 [55,80] . 而且, 转角石墨烯体系中具有非零谷陈数的拓扑平带能够带来接近量子化的拓扑压电响应, 可以用来定量地测量莫尔石墨烯中平带的谷陈数 [81] .…”

unclassified

See 1 more Smart Citation

Novel electrical properties of moiré graphene systems

Zhang¹,

Xie²,

Peng³

et al. 2023

Acta Phys. Sin.

Self Cite

View full text Add to dashboard Cite

In this review, we discuss the electronic structures, topological properties, correlated states, nonlinear optical responses, as well as phonon and electron-phonon coupling effects of moiré graphene superlattices. First, we illustrate that topologically non-trivial flat bands and moiré orbital magnetism are ubiquitous in various twisted graphene systems. In particular, the topological flat bands of magic-angle twisted bilayer graphene (TBG) can be explained from a zeroth pseudo-Landau-level picture, which can naturally explain the experimentally observed quantum anomalous Hall effect and some of the other correlated states. These topologically nontrivial flat bands may lead to nearly quantized piezoelectric response, which can be used to directly probe the valley Chern numbers in these moiré graphene systems. A simple and general chiral decomposition rule is reviewed and discussed, which can be used to predict the low-energy band dispersions of generic twisted mulilayer graphene system and alternating twisted multilayer graphene system. This review further discusses nontrivial interaction effects of magic-angle TBG such as the correlated insulator states, density wave states, cascade transitions, and nematic states, and proposes nonlinear optical measurement as an experimental probe to distinguish the different "featureless" correlated states.The phonon properties and electron-phonon coupling effects are also briefly reviewed. The novel physics emerging from band-aligned graphene-insulator heterostructres is also discussed in this review. In the end, we make a summary and an outlook about the novel physical properties of moiré superlattices, two-dimensional materials, moiré superlattices－ two dimensional materials.

show abstract

Alternating twisted multilayer graphene: generic partition rules, double flat bands, and orbital magnetoelectric effect

Cited by 15 publications

References 77 publications

Tunable correlation in twisted monolayer–trilayer graphene

Tunable correlation in twisted monolayer–trilayer graphene

The interlayer twist effectively regulates interlayer excitons in InSe/Sb van der Waals heterostructure

Novel electrical properties of moiré graphene systems

Contact Info

Product

Resources

About