共查询到15条相似文献,搜索用时 109 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
9.
基于平面波展开法研究光子晶体的带隙特性,数值模拟了横磁波和横电波在三角晶格和正方晶格构成的二维光子晶体中的带隙特性,得到了三角晶格较正方晶格更容易出现带隙,且三角晶格的横电波光子带隙较大.实验结果为光子晶体器件的设计提供理论依据. 相似文献
10.
通过引入振动力学中的连续系统离散化的思想,将一维集中质量法延伸至二维,提出一种二维声子晶体带隙特性计算的集中质量法. 进而采用该算法对两种正方晶格的二维声子晶体的带结构进行了计算,计算结果与传统的平面波展开法相符合. 通过对计算结果以及两种算法收敛性的分析,发现集中质量法的收敛性对组成声子晶体的不同材料弹性参数差不敏感,这使得该算法在计算大弹性常数差二维声子晶体的带隙特性时较平面波展开法收敛速度更快. 此外,集中质量法对二维声子晶体单元形状没有特殊要求,这使得它更加适用于声子晶体带隙特性的计算.
关键词:
声子晶体
声子带隙
集中质量法 相似文献
11.
The plane-wave method is used to determine the spin-wave spectra in nanoscale one-dimensional magnonic crystals formed by
a periodic lattice of ferromagnetic stripes. The dynamic demagnetizing field in a new formulation is used in these calculations.
The calculated spectra of spin waves are compared with experimental data taken from literature and a good agreement is obtained.
The dependence of the spin-wave spectra on magnetic material parameters consisting of magnetic stripes is systematically studied.
We proved that the experimentally found magnonic band structure with two magnonic gaps is of magnetostatic nature. 相似文献
12.
Effects of rotating noncircular scatterers on spin-wave band gaps of two-dimensional magnonic crystals 下载免费PDF全文
Using the plane-wave expansion method, the spin-wave band structures of two-dimensional magnonic crystals consisting of square arrays of different shape scatterers are calculated numerically, and the effects of rotating rectangle and hexagon scaterers on the gaps are studied, respectively. The results show that the gaps can be substantially opened and tuned by rotating the scatterers. This approach should be helpful in designing magnonic crystals with desired gaps. 相似文献
13.
C.H.O. Costa P.H.R. Barbosa F.F. Barbosa Filho M.S. Vasconcelos E.L. Albuquerque 《Solid State Communications》2010,150(47-48):2325-2328
In this work we investigate magnonic band gaps, in the terahertz (THz) frequency range, in periodic and quasiperiodic (Fibonacci sequence) magnonic crystals formed by layers of Cobalt (Co) and Permalloy (Py). Our theoretical model is based on a magnetic Heisenberg Hamiltonian in the exchange regime, together with a transfer-matrix treatment within the random-phase approximation (RPA). For periodic arrangements the bulk band structure is analogous to those found in photonic crystals, while for quasiperiodic multilayers it presents additional pass bands similar to those found in doped electronic materials. 相似文献
14.
Itinerant Topological Magnons in SU (2) Symmetric Topological Hubbard Models with Nearly Flat Electronic Bands 下载免费PDF全文
《中国物理快报》2021,(5)
We show that a suitable combination of flat-band ferromagnetism,geometry and nontrivial electronic band topology can give rise to itinerant topological magnons.An SU(2) symmetric topological Hubbard model with nearly flat electronic bands,on a Kagome lattice,is considered as the prototype.This model exhibits ferromagnetic order when the lowest electronic band is half-filled.Using the numerical exact diagonalization method with a projection onto this nearly flat band,we can obtain the magnonic spectra.In the flat-band limit,the spectra exhibit distinct dispersions with Dirac points,similar to those of free electrons with isotropic hoppings,or a local spin magnet with pure ferromagnetic Heisenberg exchanges on the same geometry.Significantly,the non-flatness of the electronic band may induce a topological gap at the Dirac points,leading to a magnonic band with a nonzero Chern number.More intriguingly,this magnonic Chern number changes its sign when the topological index of the electronic band is reversed,suggesting that the nontrivial topology of the magnonic band is related to its underlying electronic band.Our work suggests interesting directions for the further exploration of,and searches for,itinerant topological magnons. 相似文献
15.
A. V. Drozdovskii A. A. Nikitin A. B. Ustinov B. A. Kalinikos 《Technical Physics》2014,59(7):1032-1035
Microwave properties of ferrite-ferroelectric magnonic crystals are investigated for the first time. The electric and magnetic rearrangement of the band gaps in the spectrum of proper electromagnetic spin waves in such structures is demonstrated. 相似文献