Photonic Higher-Order Topological States Induced by Long Range Interactions
arXiv:1909.09199
Abstract
The discovery of topological phases has recently led to a paradigm shift in condensed matter physics, and facilitated breakthroughs in engineered photonics and acoustic metamaterials. Topological insulators (TIs) enable the generation of electronic, photonic, and acoustic modes exhibiting wave propagation that is resilient to disorder, irrespective of manufacturing precision or unpredictable defects induced by the operational environment, known as topological protection. While originally limited to a dimensionality of the protected states that is one dimension lower than the host TI material, the recent discovery of higher-order topological insulators (HOTIs) provides the potential to overcome this dimensionality limitations by offering topological protection over an extended range of dimensionalities. Here we demonstrate 2D photonic HOTI (PHOTI) with topological states two dimensions lower than the one of the host system. We consider a photonic metacrystal of distorted Kagome lattice geometry that exhibits topological bulk polarization, leading to the emergence of 1D topological edge states and of higher order 0D states confined to the corners of the structure. Interestingly, in addition to corner states due to the nearest neighbour interactions and protected by generalized chiral symmetry 1, we discover and take advantage of a new class of topological corner states sustained by long-range interactions, available in wave-based systems, such as in photonics. Our findings demonstrate that photonic HOTIs possess richer physics compared to their condensed matter counterparts, offering opportunities for engineering novel designer electromagnetic states with unique topological robustness.
arXiv comment13 pages, 4 figures
References in corpus (32)
- Topological Insulators
- Topological insulators and superconductors
- Quantum Spin Hall Effect in Graphene
- Topological Order and the Quantum Spin Hall Effect
- Photonic Floquet Topological Insulators
- Possible Realization of Directional Optical Waveguides in Photonic Crystals with Broken Time-Reversal Symmetry
- Valley contrasting physics in graphene: magnetic moment and topological transport
- Photonic Analogue of Two-dimensional Topological Insulators and Helical One-Way Edge Transport in Bi-Anisotropic Metamaterials
- Scheme to Achieve Silicon Topological Photonics
- Higher-Order Topological Insulators
- Robust optical delay lines via topological protection
- Electric Multipole Moments, Topological Multipole Moment Pumping, and Chiral Hinge States in Crystalline Insulators
- Topological Acoustics
- Analogs of quantum Hall effect edge states in photonic crystals
- -dimensional edge states of rotation symmetry protected topological states
- Reflection symmetric second-order topological insulators and superconductors
- Observation of a phononic quadrupole topological insulator
- Higher-order topological insulators and semimetals on the breathing Kagome and pyrochlore lattices
- Acoustic higher-order topological insulator on a Kagome lattice
- Demonstration of a quantized microwave quadrupole insulator with topologically protected corner states
- A topological quantum optics interface
- Higher-order topological insulators and superconductors protected by inversion symmetry
- Second-order topological insulators and superconductors with an order-two crystalline symmetry
- Observation of novel edge states in photonic graphene
- Experimental Observation of Large Chern numbers in Photonic Crystals
- Classification of topological phonons in linear mechanical metamaterials
- Realization of an acoustic third-order topological insulator
- Minimal model for higher-order topological insulators and phosphorene
- Anomalous Topological Phases and Unpaired Dirac Cones in Photonic Floquet Topological Insulators
- Lattice models with exactly solvable topological hinge and corner states
- Controlling the flow of light using the inhomogeneous effective gauge field that emerges from dynamic modulation
- Strong and weak second-order topological insulators with hexagonal symmetry and index