Topological quadratic-node semimetal in a photonic microring lattice

Graphene, with its two linearly dispersing Dirac points with opposite windings, is the minimal topological nodal configuration in the hexagonal Brillouin zone. Topological semimetals with higher-order nodes beyond the Dirac points have recently attracted considerable interest due to their rich chira...

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Bibliographic Details
Published in:Nature communications 2023-06, Vol.14 (1), p.3206-3206, Article 3206
Main Authors: Gao, Zihe, Zhao, Haoqi, Wu, Tianwei, Feng, Xilin, Zhang, Zhifeng, Qiao, Xingdu, Chiu, Ching-Kai, Feng, Liang
Format: Article
Language:English
Subjects:
142/126
639/624/399/1015
639/766/119/2792
Brillouin zones
Coexistence
Coils (windings)
Configurations
Elementary excitations
Graphene
Humanities and Social Sciences
Metalloids
multidisciplinary
Nodes
Photonics
Physical properties
Science
Science (multidisciplinary)
Topology
Transport properties
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Summary:Graphene, with its two linearly dispersing Dirac points with opposite windings, is the minimal topological nodal configuration in the hexagonal Brillouin zone. Topological semimetals with higher-order nodes beyond the Dirac points have recently attracted considerable interest due to their rich chiral physics and their potential for the design of next-generation integrated devices. Here we report the experimental realization of the topological semimetal with quadratic nodes in a photonic microring lattice. Our structure hosts a robust second-order node at the center of the Brillouin zone and two Dirac points at the Brillouin zone boundary—the second minimal configuration, next to graphene, that satisfies the Nielsen–Ninomiya theorem. The symmetry-protected quadratic nodal point, together with the Dirac points, leads to the coexistence of massive and massless components in a hybrid chiral particle. This gives rise to unique transport properties, which we demonstrate by directly imaging simultaneous Klein and anti-Klein tunnelling in the microring lattice. Topological semimetals can host coexisting higher-order topological nodes that may enable unique physical properties. Here, based on these topological principles, authors design and experimentally realise simultaneous massive and massless chiral quasiparticles in a photonic microring lattice.
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-023-38861-3