High-Magnetic-Field Tunneling Spectra of 
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-Stacked Trilayer Graphene on Graphite

Yin, Long-Jing; Shi, Lijuan; Li, Siyu; Zhang, Yu; Guo, Zihan; He, Lin

doi:10.1103/physrevlett.122.146802

Cited by 28 publications

(17 citation statements)

References 55 publications

(70 reference statements)

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“…Our measurements have been repeated on several samples showing ABCA domains, indicating the robustness of the gap values we measure. One question that arises is why ABCA graphene displays such a correlated gap, while ABC graphene has not displayed this phenomenon in previous spectroscopic measurements (28). To answer this question, we quantify the sharpness of the ABCA LDOS peak by extracting the half-width of the most prominent peak in the spectrum at each value of gate voltage.…”

Section: Resultsmentioning

confidence: 98%

Moiréless correlations in ABCA graphene

Kerelsky

Rubio-Verdú

Xian

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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Atomically thin van der Waals materials stacked with an interlayer twist have proven to be an excellent platform toward achieving gate-tunable correlated phenomena linked to the formation of flat electronic bands. In this work we demonstrate the formation of emergent correlated phases in multilayer rhombohedral graphene––a simple material that also exhibits a flat electronic band edge but without the need of having a moiré superlattice induced by twisted van der Waals layers. We show that two layers of bilayer graphene that are twisted by an arbitrary tiny angle host large (micrometer-scale) regions of uniform rhombohedral four-layer (ABCA) graphene that can be independently studied. Scanning tunneling spectroscopy reveals that ABCA graphene hosts an unprecedentedly sharp van Hove singularity of 3–5-meV half-width. We demonstrate that when this van Hove singularity straddles the Fermi level, a correlated many-body gap emerges with peak-to-peak value of 9.5 meV at charge neutrality. Mean-field theoretical calculations for model with short-ranged interactions indicate that two primary candidates for the appearance of this broken symmetry state are a charge-transfer excitonic insulator and a ferrimagnet. Finally, we show that ABCA graphene hosts surface topological helical edge states at natural interfaces with ABAB graphene which can be turned on and off with gate voltage, implying that small-angle twisted double-bilayer graphene is an ideal programmable topological quantum material.

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Section: Resultsmentioning

confidence: 98%

Moiréless correlations in ABCA graphene

Kerelsky

Rubio-Verdú

Xian

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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“…The values of tight-binding parameters γ 0,...,4 and δ have been constrained in the literature from fits to experimental data [14,31] and ab initio simulations [10,[32][33][34]. However, due to the large number of parameters and limited data availability, there exist significant discrepancies between these estimates.…”

Section: Band Structure Modelmentioning

confidence: 99%

Half- and quarter-metals in rhombohedral trilayer graphene

Zhou

Xie

Ghazaryan

et al. 2021

Nature

173

140

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“…In graphene monolayer, the Coulomb energy is compatible with the measured valley splitting at  = 0. However, at present, the approximately linear B-scaling of the valley splitting in graphene is beyond the description of any existed theory 16,37 and more theoretical works are needed to fully understand this phenomenon. Moreover, our experiment demonstrated that the valley splitting depends sensitively on the filling factor: for example, the valley splitting decreases about 25% at  = -1 even though the magnetic field is higher ( Fig.…”

mentioning

confidence: 99%

Scanning tunneling microscope study of quantum Hall isospin ferromagnetic states in the zero Landau level in a graphene monolayer

Zhang

Yin

et al. 2019

Phys. Rev. B

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A number of quantum Hall isospin ferromagnetic (QHIFM) states have been predicted in the "relativistic" zero Landau level (LL) of graphene monolayer. These states, especially the states at LL filling factor  = 0 of charge-neutral graphene, have been extensively explored in experiment. To date, identification of these high-field broken-symmetry states has mostly relied on macroscopic transport techniques. Here, we study splitting of the zero LL of graphene at partial filling and demonstrate a direct approach by imaging the QHIFM states at atomic scale with a scanning tunneling microscope. At half filling of the zero LL ( = 0), the system is in a spin unpolarized state and we observe a linear magnetic-fieldscaling of valley splitting. Simultaneously, the spin degeneracy in the two valleys is also lifted by the magnetic fields. When the Fermi level lies inside the spinpolarized states (at  = 1 or -1), the spin splitting is dramatically enhanced because of the strong many-body effects. At  = 0, we direct image the wavefunctions of the QHIFM states at atomic scale and observe an interaction-driven density wave featuring a Kekulé distortion, which is responsible for the large gap at charge neutrality point in high magnetic fields.

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High-Magnetic-Field Tunneling Spectra of ABC -Stacked Trilayer Graphene on Graphite

Cited by 28 publications

References 55 publications

Moiréless correlations in ABCA graphene

Moiréless correlations in ABCA graphene

Half- and quarter-metals in rhombohedral trilayer graphene

Scanning tunneling microscope study of quantum Hall isospin ferromagnetic states in the zero Landau level in a graphene monolayer

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