Observation of chiral edge states in gapped nanomechanical graphene

Xi, Xiang; Ma, Jingwen; Wan, Shanhong; Dong, Chun‐Hua; Sun, Xiankai

doi:10.1126/sciadv.abe1398

Cited by 50 publications

(21 citation statements)

References 42 publications

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“…In the following, we will focus on the realization of valley‐locked CESs appearing at edges or external boundaries of our VPMM, which have the topological origins from the valley‐dependent bulk topological charges that arise from the broken inversion symmetry of the underlying lattice. [ 32–34,42 ]…”

Section: Resultsmentioning

confidence: 99%

Topological Chiral Edge States in Deep‐Subwavelength Valley Photonic Metamaterials

Chen

Yan

et al. 2022

Laser & Photonics Reviews

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Topological valley photonics has emerged as a new frontier in photonics with many promising applications. Previous valley boundary transport relies on kink states at internal boundaries between two topologically distinct domains. However, recent studies have revealed a novel class of topological chiral edge states (CESs) at external boundaries of valley materials, which have remained elusive in photonics. Here, topological CESs are proposed and experimentally demonstrated in valley photonic metamaterials (VPMMs) by accurately tuning on‐site edge potentials. Moreover, the VPMMs work at deep‐subwavelength scales. Thus, the supported CESs are highly confined and self‐guiding without relying on a cladding layer to prevent leakage radiation. Via direct near‐field measurements, the bulk bandgap, the edge dispersions, and the robust edge transport passing through sharp corners, which are hallmark signatures of the CESs, are observed. This work paves a way to explore novel topological edge states in valley photonics and sheds light on robust and miniaturized photonic devices.

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Section: Resultsmentioning

confidence: 99%

Topological Chiral Edge States in Deep‐Subwavelength Valley Photonic Metamaterials

Chen

Yan

et al. 2022

Laser & Photonics Reviews

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“…Consequently, resorting to the strictly quantized WP charges, we can globally track the topological valley transport in individual AVMs with 3D Weyl topology. Below we start with the less explored single-crystal systems [8,9,42] and then generalize our study to the more popular domain-wall systems. Gapless synthetic surface states.…”

Section: Introductionmentioning

confidence: 99%

Tracking Valley Topology with Synthetic Weyl Paths

et al. 2022

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Inspired by the newly emergent valleytronics, great interest has been attracted to the topological valley transport in classical metacrystals. The presence of nontrivial domain-wall states is interpreted with a concept of valley Chern number, which is well defined only in the limit of small bandgap. Here, we propose a new visual angle to track the intricate valley topology in classical systems. Benefiting from the controllability of our acoustic metacrystals, we construct Weyl points in synthetic three-dimensional momentum space through introducing an extra structural parameter (rotation angle here). As such, the two-dimensional valley-projected band topology can be tracked with the strictly quantized topological charge in three-dimensional Weyl crystal, which features open surface arcs connecting the synthetic Weyl points and gapless chiral surface states along specific Weyl paths. All theoretical predictions are conclusively identified by our acoustic experiments. Our findings may promote the development of topological valley physics, which is less well-defined yet under hot debate in multiple physical disciplines.

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“…However, the increase in size brings electrical, thermal, and mechanical performance [6][7].In particular, the high-quality electrical properties of graphene are affected by the formation of edges. Edge states are known to play an essential role in the quantum Hall regime [8][9]. For graphene, particularly, it was shown by scanning tunneling microscopy and spectroscopy that the quantum Hall edge states display confinement characteristics by an atomically sharp edge, without edge-state reconstruction [10].…”

Section: Introductionmentioning

confidence: 99%

Magnetic Field Effects on Charge and Current Density in Finite Monolayer Graphene

Gonzalez¹,

Quintero‐Orozco

Castro

2021

rev.ing.univ.Medellin

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In this work, we study the effects of an external magnetic field on the charge and current density in finite monolayer graphene, i.e., with zig-zag and armchair edges. We use the tight-binding model to include the effects of the magnetic field and the effect of the edges. By using the transmission probability and analyzing the local density of states (charge density) ob- tained from Green’s function method, we find an energy region where the wave functions are more localized in the edges and, consequently, the current flow across the borders. On the other hand, for energies close to Landau levels, the charge and current density are localized on the bulk of the system.

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Observation of chiral edge states in gapped nanomechanical graphene

Cited by 50 publications

References 42 publications

Topological Chiral Edge States in Deep‐Subwavelength Valley Photonic Metamaterials

Topological Chiral Edge States in Deep‐Subwavelength Valley Photonic Metamaterials

Tracking Valley Topology with Synthetic Weyl Paths

Magnetic Field Effects on Charge and Current Density in Finite Monolayer Graphene

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