Inverse design of quantum spin hall-based phononic topological insulators

Nanthakumar, S.S.; Zhuang, Xiaoying; Park, Harold S.; Nguyen, Chuong V.; Chen, Yanyu; Rabczuk, Timon

doi:10.1016/j.jmps.2019.01.009

Cited by 87 publications

(33 citation statements)

References 58 publications

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“…These experimental results differ from all of the prior research [15,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] that have only demonstrated the twoway partitioning of topological modes. Our design is wholly contingent upon the geometrical properties of the square and rectangular lattices.…”

Section: B Three-way Beam Splitting For Topological Acoustic Modescontrasting

confidence: 99%

“…Numerous examples of two-way beam splitters have been shown [15,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] that leverage the geometry of graphenelike hexagonal structures. The restriction to two-way beam splitting is due to a conservation of a topological charge inherent within graphenelike structures [17]; to obtain these three-way beam splitters, square, or rectangular, lattice structures must be used and not the hexagonal graphenelike structures that are prevalent in the topological community [15,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. Venturing beyond beam splitters, a longstanding desire within the phononic's sister photonics community has been to mold the flow of light through and around complex optoelectronic "photonic cities," as shown on the cover of the now classic book by Joannopoulos et al [43].…”

Section: Introductionmentioning

confidence: 99%

“…Because of the underlying topological nature of our designs, wave transport is both more robust and also tunable by geometry; hence, a wave splitter can be seamlessly changed into a wave steerer by altering a select portion of the structured medium. The geometrical tunability, the topological robustness, and the three-way partitioning of energy are the three crucial advantages of our experimental design over competing methods [15,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. The phononic circuits created demonstrate the versatility of the underlying mechanisms to efficiently navigate acoustic waves over a broadband range of frequencies.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Acoustic Topological Circuitry in Square and Rectangular Phononic Crystals

et al. 2021

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We use square and rectangular phononic crystals to create experimental realizations of complex topological phononic circuits. The exotic topological transport observed is wholly reliant upon the underlying structure that must belong to either a square or rectangular lattice system and not to any hexagonal-based structure. The phononic system we use consists of a periodic array of square steel bars that partitions acoustic waves in water over a broadband range of frequencies (about 0.5 MHz). An ultrasonic transducer launches an acoustic pulse that propagates along a domain wall, before encountering a nodal point, from which the acoustic signal partitions towards three exit ports. Numerical simulations are performed to clearly illustrate the highly resolved edge states as well as corroborate our experimental findings. To achieve complete control over the flow of energy, we need to create power division and redirection devices. The tunability afforded by our designs, in conjunction with the topological robustness of the modes, will lead to incorporation into acoustical devices.

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Section: B Three-way Beam Splitting For Topological Acoustic Modescontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Acoustic Topological Circuitry in Square and Rectangular Phononic Crystals

et al. 2021

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“…Considerable progress was made in the experimental realization of such states in all the above mentioned areas, in particular in electronic systems (see refs. [] and references therein), where such states were introduced initially, mechanical systems, where tunable phononic topological insulators have been designed using geometrically induced effects of spin–orbit coupling,, acoustics, cold atoms in optical lattices, atomic Bose–Einstein condensates, and most notably in optical systems (see ref. []), including gyromagnetic photonic crystals, semiconductor quantum wells, arrays of coupled resonators, metamaterial superlattices, and helical waveguide arrays .…”

Section: Introductionmentioning

confidence: 99%

Finite‐Dimensional Bistable Topological Insulators: From Small to Large

Zhang

Chen

Kartashov

et al. 2019

Laser & Photonics Reviews

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Photonic topological insulators supporting unidirectional topologically protected edge states represent an attractive platform for the realization of disorder‐ and backscattering‐immune transport of edge excitations in both linear and nonlinear regimes. While the properties of the edge states at unclosed interfaces of two bulk media with different topologies are known, the existence of edge states in practical finite‐dimensional topological insulators fully immersed in a nontopological environment remains largely unexplored. In this work, using realistic polariton topological insulators built from small‐size honeycomb arrays of microcavity pillars as an example, it is shown how topological properties of the system build up upon gradual increase of its dimensionality. To account for the dissipative nature of the polariton condensate forming in the array of microcavity pillars, the impact of losses and resonant pump leading to rich bistability effects in this system is considered. The mechanism is described in accordance with which trivial‐phase pump “selects” and excites specific nonlinear topological edge states circulating along the periphery of the structure in the azimuthal direction, dictated by the direction of the external applied magnetic field. The possibility of utilization of vortex pump with different topological charges for selective excitation of different edge currents is also shown.

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“…Inverse design methods adopt topology and shape optimization to meet requirements like larger topological band width and flexible operating frequency ranges. The inverse design approaches are based on achieving intended unit cell band structure [22,23] or localizing energy in specific paths of the periodic structure [24]. Reconfigurability or tunability by the presence of buckling members in lattices [25], pre-stressing soft phononic crystals [26] or embedding shunted piezoelectric patches [27,28] overcomes the constraint of fixed wave paths in case of passive phononic metamaterials.…”

Section: Introductionmentioning

confidence: 99%

Inverse design of reconfigurable piezoelectric topological phononic plates

Nguyen¹,

Nanthakumar²,

Zhuang³

et al. 2021

Preprint

Self Cite

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We present a methodology to perform inverse analysis on reconfigurable topological insulators for flexural waves in plate-like structures. First the unit cell topology of a phononic plate is designed, which offers two-fold degeneracy in the band structure by topology optimization. In the second step, piezoelectric patches bonded over the substrate plate are connected to an external circuit and used appropriately to break space inversion symmetry. The space inversion symmetry breaking opens a topological band gap by mimicking quantum valley Hall effect. Numerical simulations demonstrate that the topologically protected edge state exhibits wave propagation without backscattering and is immune to disorders. Predominantly, the proposed idea enables real-time reconfigurability of the topological interfaces in waveguide applications.

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Inverse design of quantum spin hall-based phononic topological insulators

Cited by 87 publications

References 58 publications

Acoustic Topological Circuitry in Square and Rectangular Phononic Crystals

Acoustic Topological Circuitry in Square and Rectangular Phononic Crystals

Finite‐Dimensional Bistable Topological Insulators: From Small to Large

Inverse design of reconfigurable piezoelectric topological phononic plates

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