Deterministic interface modes in two-dimensional acoustic systems

2020 ◽  
pp. 2150010
Author(s):  
Shao-Yong huo ◽  
Hong-Bo Huang ◽  
Lin-Jun Wang ◽  
Jiu-Jiu Chen
Keyword(s):  
Phase Transitions ◽  
Acoustic Waves ◽  
Tight Binding ◽  
Interface State ◽  
Interface States ◽  
Square Lattice ◽  
Two Dimensional ◽  
Practical Applications ◽  
Acoustic Interface ◽  
Sonic Crystals

The interface state in two-dimensional (2D) sonic crystals (SCs) was obtained based on trying or cutting approach, which greatly limits its practical applications. In this paper, we theoretically demonstrate that one category of interface states can deterministically exist at the boundary of two square-lattice SCs due to the geometric phase transitions of bulk bands. First, we derive a tight-binding formalism for acoustic waves and introduce it into the 2D case. Furthermore, the extended 2D Zak phase is employed to characterize the topological phase transitions of bulk bands. Moreover, the topological interface states can be deterministically found in the nontrivial bandgap. Finally, two kinds of SCs with the [Formula: see text] symmetry closely resembling the 2D Su–Schrieffer–Heeger (SSH) model are proposed to realize the deterministic interface states. We find that tuning the strength of intermolecular coupling by contacting or expanding the scatterers can effectively induce the bulk band inversion between the trivial and nontrivial crystals. The presence of acoustic interface states for both cases is further demonstrated. These deterministic interface states in 2D acoustic systems will be a great candidate for future waveguide applications.

Band Structure in a Sustainable Sonic Crystal

2019 ◽  
Vol 958 ◽  
pp. 75-80
Author(s):  
Edson Jansen Pedrosa Miranda Jr. ◽  
S.F. Rodrigues ◽  
J.M.C. dos Santos
Keyword(s):  
Band Structure ◽  
Cross Section ◽  
Cross Sections ◽  
Acoustic Waves ◽  
Band Gaps ◽  
Square Lattice ◽  
Host Medium ◽  
Fiber Cross Section ◽  
Sonic Crystal ◽  
Sonic Crystals

During the last few decades many researchers have been interested in acoustic wave propagation in artificial periodic composites known as sonic crystals. Sonic crystals have received renewed attention because they exhibit acoustic band gaps where there are only evanescent waves. Sonic crystals consist of a periodic array of scatterers embedded in a host medium. The host medium and/or scatterers are fluids. We investigate the band structure of acoustic waves propagating in a sustainable sonic crystal composed by miriti fibers and air, regarding square and triangular lattices. Miriti fibers are extracted from buriti palm petiole (Mauritia flexuosa Mart.), which is a typical specie that grows in Amazonian region. We also study the influence of miriti fiber cross section, i.e. circular, hollow circular, square and rotated square with a 45° angle of rotation with respect to x, y axes. Plane wave expansion method is used to solve the wave equation. Acoustic band gaps are observed for all miriti fiber cross sections and lattices. The best performances of the sustainable sonic crystal are for triangular lattice, regarding circular and rotated square miriti fiber cross sections, and for square lattice with circular miriti fiber cross section. We suggest that the sustainable sonic crystal should be feasible for noise management.

Topological phase transition of two-dimensional topological polaritons

2017 ◽  
Vol 31 (11) ◽  
pp. 1750070
Author(s):  
Zimeng Chi ◽  
Xiaoyong Guo ◽  
Zaijun Wang
Keyword(s):  
Phase Transitions ◽  
Energy Gap ◽  
Tight Binding ◽  
Quantum Spin ◽  
Generic Model ◽  
Topological Phase ◽  
Two Dimensional ◽  
Strongly Coupled ◽  
Bulk Energy ◽  
Topological Phase Transitions

Topological phase transitions of a two-dimensional topologically nontrivial polaritonic system are studied. A generic model of semiconductor excitons strongly coupled with tailored photonic modes is considered. We introduce a pseudospin operator, measuring the polariton polarization between photonic-like and excitonic-like. The associated pseudospin spectrum and pseudospin Chern numbers are calculated. It is shown that the pseudospin Chern number phase diagram exhibits certain features resembling the topological phase of quantum-spin-Hall-like. Moreover, a series of topological phase transitions may occur with the closing of the bulk energy gap or the pseudospin spectrum gap. In a tight-binding form, the edge-mode simulation is done numerically to confirm the analytically results.

Plasmon excitations in doped square-lattice atomic clusters

2017 ◽  
Vol 31 (30) ◽  
pp. 1750233 ◽  
Author(s):  
Yaxin Wang ◽  
Ya-Bin Yu
Keyword(s):  
Tight Binding ◽  
Blue Shift ◽  
Coulomb Repulsion ◽  
Atomic Clusters ◽  
Red Shift ◽  
Square Lattice ◽  
Local Mode ◽  
Two Dimensional ◽  
Binding Model ◽  
Dopant Atoms

Employing the tight-binding model, we theoretically study the properties of the plasmon excitations in doped square-lattice atomic clusters. The results show that the dopant atoms would blur the absorption spectra, and give rise to extra plasmon resonant peaks as reported in the literature; however, our calculated external-field induced oscillating charge density shows that no obvious evidences indicate the so-called local mode of plasmon appearing in two-dimensional-doped atomic clusters, but the dopants may change the symmetry of the charge distribution. Furthermore, we show that the disorder of the energy level due to dopant makes the absorption spectrum has a red- or blue-shift, which depends on the position of impurities; disorder of hopping due to dopant makes a blue- or red-shift, a larger (smaller) hopping gives a blue-shift (red-shift); and a larger (smaller) host-dopant and dopant–dopant intersite coulomb repulsion induces a blue-shift (red-shift).

Resonance Modes in Multiple Quantum Wells Structure of Two-Dimensional Photonic Crystal

2012 ◽  
Vol 457-458 ◽  
pp. 85-88
Author(s):  
Chun Mei Zhang ◽  
Tao Meng ◽  
Yan Ping Hao ◽  
Fu Ping Liu
Keyword(s):  
Photonic Crystal ◽  
Quantum Wells ◽  
Tight Binding ◽  
Multiple Quantum Wells ◽  
Square Lattice ◽  
Multiple Quantum ◽  
Two Dimensional ◽  
Resonance Modes ◽  
Frequency Split ◽  
Two Dimensional Photonic Crystal

We have theoretically discussed the resonance modes in a two-dimensional photonic multiple quantum wells structure (QWs) consists of one photonic crystal with square lattice of parallel dielectric circular columns in air and some layers of columns are removed at constant intervals. The generation and frequency split of resonance modes are observed and explained with tight-binding approach. The effect of the interaction distance on the frequency split is also discussed.

Negative refraction of acoustic waves in two-dimensional sonic crystals

2005 ◽  
Vol 72 (3) ◽  
Author(s):  
Liang Feng ◽  
Xiao-Ping Liu ◽  
Yan-Bin Chen ◽  
Zhi-Peng Huang ◽  
Yi-Wei Mao ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Negative Refraction ◽  
Two Dimensional ◽  
Sonic Crystals

scholarly journals Phase transitions of antiferromagnetic Ising spins on the zigzag surface of an asymmetrical Husimi lattice

2019 ◽  
Vol 6 (3) ◽  
pp. 181500 ◽  
Author(s):  
Ran Huang ◽  
Purushottam D. Gujrati
Keyword(s):  
Phase Transitions ◽  
Ising Model ◽  
Spontaneous Magnetization ◽  
Square Lattice ◽  
Two Dimensional ◽  
Simple Formulation ◽  
First Order ◽  
Husimi Lattice ◽  
Antiferromagnetic Ising Model ◽  
Ising Spins

An asymmetrical two-dimensional Ising model with a zigzag surface, created by diagonally cutting a regular square lattice, has been developed to investigate the thermodynamics and phase transitions on surface by the methodology of recursive lattice, which we have previously applied to study polymers near a surface. The model retains the advantages of simple formulation and exact calculation of the conventional Bethe-like lattices. An antiferromagnetic Ising model is solved on the surface of this lattice to evaluate thermal properties such as free energy, energy density and entropy, from which we have successfully identified a first-order order–disorder transition other than the spontaneous magnetization, and a secondary transition on the supercooled state indicated by the Kauzmann paradox.

Propagation of Acoustic Waves in Periodic and Random Two-dimensional Composite Media

1997 ◽  
Vol 12 (8) ◽  
pp. 2207-2212 ◽  
Author(s):  
J. O. Vasseur ◽  
P. A. Deymier
Keyword(s):  
Transmission Spectrum ◽  
Acoustic Waves ◽  
Power Spectra ◽  
Periodic Array ◽  
Square Lattice ◽  
Two Dimensional ◽  
Composite Media ◽  
Random Array ◽  
The One ◽  
High Degree

Transmission of acoustic waves in two-dimensional composite media composed of arrays of Duralumin cylindrical inclusions embedded in a poly vinyl chloride (PVC) matrix is studied. Experimental and theoretical results for the transmission spectrum of a periodic array of cylinders organized on a square lattice are reported. Local gaps in the first two-dimensional Brillouin zone are predicted and observed. The experimental measurements of power spectra for a random array of inclusions show a weak correlation between disorder and acoustic absorptions up to a high degree of disorder. Only in the case of highly random arrangements does the transmission spectrum diverge from the one obtained with a periodic array of inclusions.

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