Pseudospin induced topological corner state at intersecting sonic lattices

Zhang, Zhiwang; Hu, Bolun; Liu, Feng; Cheng, Ying; Liu, Xiaojun; Christensen, Johan

doi:10.1103/physrevb.101.220102

Cited by 35 publications

(14 citation statements)

References 53 publications

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“…Thus we expect our findings would bring new insights and open interesting directions in this field. Finally, we would like to note that it is certainly interesting to see whether dual-polarization SPTI could be constructed in PCs having hexagonal symmetry [61][62][63].…”

Section: Discussionmentioning

confidence: 99%

Dual-Polarization Second-Order Photonic Topological Insulators

et al. 2021

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Second-order photonic topological insulators that host highly localized corner states resilient to defects, are opening new routes towards developing fascinating photonic devices. However, the existing works on second-order photonic topological insulators have mainly focused on either transverse magnetic or transverse electric modes. In this paper, we propose a dual-polarization topological photonic crystal structure for both transverse magnetic and transverse electric modes through topology optimization. Simple tight-binding lattice models are constructed to reveal the topological features of the optimized photonic crystal structure in a transparent way. The optimized dual-polarization second-order photonic topological insulator hosts four groups of corner states with different profiles and eigenfrequencies for both the transverse magnetic and transverse electric modes. Moreover, the robustness of theses corner states against defects is explicitly demonstrated. Our results offer opportunities for developing polarization-independent topological photonic devices.

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Section: Discussionmentioning

confidence: 99%

Dual-Polarization Second-Order Photonic Topological Insulators

et al. 2021

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“…Introduction of spin degrees of freedom and spin-orbit interactions originally proposed in condensed-matter systems [19,20], has naturally lead to the discovery of new topological classes generalizing the existing ones, such as quantum spin Hall effect [21][22][23][24][25], or spinful versions of higher-order topological structures [26][27][28][29][30][31]. However, condensed matter systems pose stringent limitations on possible values of the spin and its couplings to the orbital motion.…”

Section: Introductionmentioning

confidence: 99%

Multipole higher-order topology in a multimode lattice

Mazanov¹,

Kupriianov²,

Savelev³

et al. 2022

Preprint

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The concepts of topology have a profound impact on physics research spanning the fields of condensed matter, photonics and acoustics and predicting topological states that provide unprecedented versatility in routing and control of waves of various nature. Higher-order topological insulators further expand this plethora of possibilities towards extended range of structure dimensionalities. Here, we put forward a novel class of twodimensional multipolar higher-order topological insulators that arise due to the interference of the degenerate modes of the individual meta-atoms generalizing the mechanism of spin-orbit coupling in condensed matter. We prove that this model features disorder-robust corner modes and cannot be reduced to the known crystalline topological phases or conventional quadrupole insulators, providing the first example of multipolar topology in a C3-symmetric lattice. The multimode nature of the lattice enables flat bands and corner states with extreme localization and allows to tune the topology of the bands via on-site properties. We support our predictions by assembling the designed structure and observing multipolar topological corner states experimentally.

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“…For example, in two-dimensional (2D) systems, a second-order topological insulator (SOTI) supports the zero-dimensional (0D) localized corner states. Moreover, these lower-dimensional boundary states provide versatile routes to extraordinarily manipulate wave fields, which have led to extensive researches in the classical wave systems, such as elastics [6][7][8], microwaves [9], electric circuits [10], photonics [11][12][13][14][15], and acoustics [16][17][18][19][20][21][22][23][24][25][26]. Therein, the acoustic SOTIs have been experimentally proposed based on the enclosed resonators connected by the coupled tubes [16,17,[22][23][24] and the rigid scatterers in the 2D waveguides [19].…”

Section: Introductionmentioning

confidence: 99%

Glided acoustic higher-order topological insulators based on spoof surface acoustic waves

et al. 2022

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Higher-order topological insulator (HOTI) hosts both gapped edge states and in-gap corner states, which has garnered considerable attentions in the field of condensed matter physics, and most recently is further extended to the classical wave systems. Conventional acoustic metamaterials have intrinsic material and design limitations that prevent them from being used to create such states in subwavelength scale with function reconfigurability. Recently, the acoustic second-order topological insulators (SOTIs) composed of locally resonant metamaterials were reported to solve the problem, where the topological phase transition is induced by shrinking/expanding metamolecules. Here, we propose an acoustic SOTI in subwavelength scale by another protocol, i.e. gliding metamolecules, and the SOTI is pinned in the nontrivial region without the regular topological phase transition. Soda cans metamaterials in free space are utilized to support the spoof surface acoustic waves (SAWs). With varying the introduced glided angle, the switching from the bulk to edge and corner states can be achieved accordingly. Furthermore, we not only experimentally observe this state switching process, but also illustrate the robustness of the topological corner states against various defects. Our results provide versatile ways to launch acoustic lower-dimensional topological states that might lead to interesting sound concentration applications.

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Pseudospin induced topological corner state at intersecting sonic lattices

Cited by 35 publications

References 53 publications

Dual-Polarization Second-Order Photonic Topological Insulators

Dual-Polarization Second-Order Photonic Topological Insulators

Multipole higher-order topology in a multimode lattice

Glided acoustic higher-order topological insulators based on spoof surface acoustic waves

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