Quantum Hall phase in graphene engineered by interfacial charge coupling

Wang, Yaning; Gao, Xiang; Yang, Kaining; Gu, Pingfan; Lü, Xin; Zhang, Shihao; Gao, Y.C.; Ren, Naijie; Dong, Baojuan; Jiang, Yuhang; Watanabe, Kenji; Taniguchi, Takashi; Kang, Jun; Lou, Wenkai; Mao, Jinhai; Liu, Jianpeng; Yu, Yongqin; Han, Zheng; Chang, Kai; Zhang, Jing; Zhang, Z.D.

doi:10.1038/s41565-022-01248-4

Cited by 31 publications

(35 citation statements)

References 49 publications

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“…2(d). This perfectly explains the recent experiment in gate-controlled graphene-CrOCl heterostructure, in which the Fermi velocity around CNP is significantly enhanced compared to noninteracting value at slight carrier doping, such that robust quantum Hall effect can be observed under tiny vertical magnetic fields (∼ 0.1 T) and high temperatures [19]. We note that the EC state may be stabilized by vertical magnetic fields even when the carrier density in the substrate exceeds the zero-field threshold value [43,44], which in turn boosts the low-field, high-temperature quantum Hall effect in the graphene layer due to the scenario discussed above.…”

Section: Coulomb Interactions In Graphenesupporting

confidence: 87%

“…Especially, how the mutual couplings would affect the interacting electronic states in both systems. Inspired by recent pioneering experiments in CrOCl-graphene [19], 1T-TaS 2 -graphene [20], and CrI 3 -graphene [21] heterostructures, here we propose that such a scenario (of interacting Dirac fermions coupled with the correlated electrons in charge doped TMO/TMC insulators) can be realized in graphene-insulator heterostructures with gate tunable band alignment. In this work, we show that, by virtue of the interlayer Coulomb coupling between the interacting electrons in the two layers, intriguing correlated physics that cannot be seen in either individual layer would emerge in a cooperative and synergistic manner in such band-aligned graphene-insulator heterostructures.…”

Section: Introductionmentioning

confidence: 95%

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Synergistic correlated states and nontrivial topology in coupled graphene-insulator heterostructures

Lü

Zhang

Gao

et al. 2023

Preprint

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In this work, we study the synergistic correlated states in two distinct types of interacting electronic systems coupled by interlayer Coulomb interactions. We propose that this scenario can be realized in a new type of Coulomb-coupled graphene-insulator heterostructures with gate tunable band alignment. We find that, by virtue of the interlayer Coulomb coupling between the interacting electrons in the two layers, intriguing correlated physics that is not seen in either individual layer emerges in a cooperative and synergistic manner. Specifically, as a result of the band alignment, charge carriers can be transferred between graphene and the substrate under the control of gate voltages, which can yield a long-wavelength electronic crystal at the surface of the substrate. This electronic crystal exerts a superlattice Coulomb potential on the Dirac electrons in graphene, which generates subbands with reduced non-interacting Fermi velocity. As a result, $e$-$e$ Coulomb interactions within graphene would play a more important role, giving rise to a gapped Dirac state at the charge neutrality point, accompanied by interaction-enhanced Fermi velocity. Moreover, the superlattice potential can give rise to topologically nontrivial subband structures which are tunable by superlattice's constant and anisotropy. Reciprocally, the electronic crystal formed in the substrate can be substantially stabilized in such coupled bilayer heterostructure by virtue of the cooperative interlayer Coulomb coupling. We further perform high-throughput first principles calculations to identify a number of promising insulating materials as candidate substrates for graphene to demonstrate these effects. Our findings provide new insights into the physics of correlated and topological electronic states in graphene-based heterostructures.

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Section: Coulomb Interactions In Graphenesupporting

confidence: 87%

Section: Introductionmentioning

confidence: 95%

Synergistic correlated states and nontrivial topology in coupled graphene-insulator heterostructures

Lü

Zhang

Gao

et al. 2023

Preprint

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“…最后, 本综述将讨论一类新型石墨烯异质结体系: 能带对齐的石墨烯和绝缘衬底形成的异质结体系中的新奇物理. 通过门电压调控的电荷转移, 在绝缘衬底上的载流子由于长程库仑作用可以形成长程电荷序, 并与石墨烯中的狄拉克费米子耦合, 进而降低狄拉克电子的非相互作用费米速度 [86] , 让电子间库仑相互作用效应更加显著, 衍生出新的关联拓扑物态 [86,87] . (d)魔角双层石墨烯的能带.…”

Section: 而在各类转角多层石墨烯体系中平带在半填充时unclassified

“…(a) Flat bands of magic-angle TBG with the octupolar-type phonon modes under frozen mode approximation [85] ; (b) increasing bandgap as a function of average displacement amplitudes [85] ; (c) strength of electron-phonon coupling verse Fermi level in the magic-angle TBG [85] ; (d) charge order with the quadrupolar-type phonon modes under frozen mode approximation [85] . Lu等 [86] 和Wang等 [87] 指出, 如果将石墨烯放置于具有长程电荷序的绝缘衬底之上, 会构成一种新型二维材料异质结体系(见图9(a)). 长程电荷序的形成本身也依赖于强电子间库仑相互作用, 如低浓度的二维电子气在长程库仑作用的驱动下会进入到维格纳晶体态 [187][188][189] 为衬底的单层石墨烯器件中实现 [87,190,191] .…”

Section: 魔角双层石墨烯的电声耦合效应mentioning

confidence: 99%

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Novel electrical properties of moiré graphene systems

Zhang¹,

Xie²,

Peng³

et al. 2023

Acta Phys. Sin.

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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.

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Gate‐Tunable Spin Hall Effect in Trilayer Graphene/Group‐IV Monochalcogenide van der Waals Heterostructures

Yang,

Chi,

Avedissian

et al. 2024

Adv Funct Materials

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Spintronic devices require materials that facilitate effective spin transport, generation, and detection. In this regard, graphene emerges as an ideal candidate for long‐distance spin transport owing to its minimal spin‐orbit coupling, which, however, limits its capacity for effective spin manipulation. This problem can be overcome by putting spin‐orbit coupling materials in close contact with graphene leading to spin‐orbit proximity and, consequently, efficient spin‐to‐charge conversion through mechanisms such as the spin Hall effect. Here, the gate‐dependent spin Hall effect in trilayer graphene proximitized with tin sulfide (SnS) is reported and quantified, a group‐IV monochalcogenide that has recently been predicted to be a viable alternative to transition‐metal dichalcogenides for inducing strong spin‐orbit coupling in graphene. The spin Hall angle exhibits a maximum around the charge neutrality point of graphene up to room temperature. The findings expand the library of materials that induce spin‐orbit coupling in graphene to a new class, group‐IV monochalcogenides, thereby highlighting the potential of 2D materials to pave the way for the development of innovative spin‐based devices and future technological applications.

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Quantum Hall phase in graphene engineered by interfacial charge coupling

Cited by 31 publications

References 49 publications

Synergistic correlated states and nontrivial topology in coupled graphene-insulator heterostructures

Synergistic correlated states and nontrivial topology in coupled graphene-insulator heterostructures

Novel electrical properties of moiré graphene systems

Gate‐Tunable Spin Hall Effect in Trilayer Graphene/Group‐IV Monochalcogenide van der Waals Heterostructures

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