Magnetically-defined topological edge plasmons in edgeless electron gas

Abstract

Topological materials bear gapped excitations in bulk yet protected gapless excitations at boundaries. Magnetoplasmons (MPs), as high-frequency density excitations of two-dimensional electron gas (2DEG) in a perpendicular magnetic field, embody a prototype of band topology for bosons. The time-reversal-breaking magnetic field opens a topological gap for bulk MPs up to the cyclotron frequency; topologically-protected edge magnetoplasmons (EMPs) bridge the bulk gap and propagate unidirectionally along system's boundaries. However, all the EMPs known to date adhere to physical edges where the electron density terminates abruptly. This restriction has made device application extremely difficult. Here we demonstrate a new class of topological edge plasmons -- domain-boundary magnetoplasmons (DBMPs), within a uniform edgeless 2DEG. Such DBMPs arise at the domain boundaries of an engineered sign-changing magnetic field and are protected by the difference of gap Chern numbers (+/-1) across the magnetic domains. They propagate unidirectionally along the domain boundaries and are immune to domain defects. Moreover, they exhibit wide tunability in the microwave frequency range under an applied magnetic field or gate voltage. Our study opens a new direction to realize high-speed reconfigurable topological devices.

7 pages, 6 figures

References in corpus (23)

• Topological insulators and superconductors
• Topological Photonics
• The physics of exceptional points
• Analogs of quantum Hall effect edge states in photonic crystals
• Temperature dependent transport in suspended graphene
• Topological Band Theory for Non-Hermitian Hamiltonians
• Non-Hermitian Chern bands
• Topologically-protected refraction of robust kink states in valley photonic crystals
• Infrared nanoscopy of Dirac plasmons at the graphene-SiO2 interface
• Evidence for a New Dissipationless Regime in 2D Electronic Transport
• Topological chiral magnonic edge mode in a magnonic crystal
• Topological Polaritons
• Topological Origin of Equatorial Waves
• Infrared Topological Plasmons in Graphene
• Plasmon Weyl Degeneracies in Magnetized Plasma
• Quantized chiral edge conduction on reconfigurable domain walls of a magnetic topological insulator
• Topological magnetoplasmon
• Bulk-edge correspondence for topological photonic continua
• On-Chip Microwave Quantum Hall Circulator
• Topological Wave-Guiding Near an Exceptional Point: Defect-Immune, Slow-Light, Loss-Immune Propagation
• Intrinsic and extrinsic decay of edge magnetoplasmons in graphene
• Topologically protected excitons in porphyrin thin films
• Microwave spectroscopic studies of the bilayer electron solid states at low Landau filling in a wide quantum well

Cited by in corpus (9)

• Anomalous bulk-edge correspondence in continuous media
• Hybrid topological magnon-phonon modes in honeycomb and kagome lattices
• Topological spin-plasma waves
• Twisted magnetic topological insulators
• Berry curvature for coupled waves of magnons and electromagnetic waves
• Co-existing topological and Volkov-Pankratov plasmonic edge states in magnetized graphene
• Coupled pair of one and two dimensional magneto-plasmons on electrons on helium
• Localized structures in three-field models: geometrically constrained configurations and the first-order framework
• Equatorial magnetoplasma waves