Gate-Tunable Proximity Effects in Graphene on Layered Magnetic Insulators

Tseng, Chun-Chih; Song, Tiancheng; Jiang, Qianni; Lin, Zhong; Wang, Chong; Suh, Jaehyun; Watanabe, Kenji; Taniguchi, Takashi; McGuire, Michael A.; Chu, Jiun‐Haw; Cobden, David; Xu, Xiaodong; Yankowitz, Matthew

doi:10.1021/acs.nanolett.2c02931

Cited by 29 publications

(25 citation statements)

References 39 publications

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“…When systematically considering the interplay between generic long-range Coulomb superlattice potentials in a number of materials coupled with graphene, our separate theoretical work suggests that such e−e interaction in graphene indeed enhances the Fermi velocity dramatically and in the meantime opens a gap at the CNP 34 . It came to our notice that similar phenomena were also recently seen, such as in graphene-CrI 3 system 35 . Based on the above analysis, we plotted a schematic phase diagram (Fig.…”

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confidence: 83%

Quantum Hall phase in graphene engineered by interfacial charge coupling

et al. 2022

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The quantum Hall effect can be substantially affected by interfacial coupling between the host two-dimensional electron gases and the substrate, and has been predicted to give rise to exotic topological states. Yet the understanding of the underlying physics and the controllable engineering of this interaction remains challenging. Here we demonstrate the observation of an unusual quantum Hall effect, which differs markedly from that of the known picture, in graphene samples in contact with an antiferromagnetic insulator CrOCl equipped with dual gates. Two distinct quantum Hall phases are developed, with the Landau levels in monolayer graphene remaining intact at the conventional phase, but largely distorted for the interfacial-coupling phase. The latter quantum Hall phase is even present close to the absence of a magnetic field, with the consequential Landau quantization following a parabolic relation between the displacement field and the magnetic field. This characteristic prevails up to 100 K in a wide effective doping range from 0 to 1013 cm−2.

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confidence: 83%

Quantum Hall phase in graphene engineered by interfacial charge coupling

et al. 2022

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“…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: 94%

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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“…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] . 并度), 必须大于临界值 [192] .…”

Section: 魔角双层石墨烯的电声耦合效应unclassified

“…我们相信在莫尔超晶格体系中的研究不会局限于石墨烯体系, 而是会延伸到包含过渡金属二硫化物 [207][208][209][210][211][212][213][214][215][216][217][218][219] 、二维磁性半导体 [220][221][222][223] 、石墨烯-绝缘体异质结 [87,190,191] 等一系列的莫尔超晶格异质结体系. 实验上已经成功制备了一系列过渡金属二硫化物的莫尔体系, 并观测到了非常规莫尔激子 [207][208][209][210] 、关联绝缘态 [211][212][213][214] 、轨道铁磁态 [211] 和非线性霍尔效应 [215,224] 等一系列新奇现象.…”

Section: 相互作用效应unclassified

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 Proximity Effects in Graphene on Layered Magnetic Insulators

Cited by 29 publications

References 39 publications

Quantum Hall phase in graphene engineered by interfacial charge coupling

Quantum Hall phase in graphene engineered by interfacial charge coupling

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

Novel electrical properties of moiré graphene systems

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