期刊
NEW JOURNAL OF PHYSICS
卷 24, 期 3, 页码 -出版社
IOP Publishing Ltd
DOI: 10.1088/1367-2630/ac575a
关键词
topological semimetal; metamaterial; Dirac point; topological phase transition
资金
- National Postdoctoral Program for Innovative Talents of China [BX20200050]
- National Key R&D Program of China [2021YFA1401200]
- Beijing Outstanding Young Scientist Program [BJJWZYJH01201910007022]
- National Natural Science Foundation of China [12104046, U21A20140, 92050117]
- Fok Ying-Tong Education Foundation of China [161009]
- Beijing Municipal Science & Technology Commission, Administrative Commission of Zhongguancun Science Park [Z211100004821009]
In this study, an acoustic metamaterial with Dirac points is demonstrated by designing the sign of coupling terms. The transition from 3D Dirac point to Weyl points can be obtained by tuning the coupling parameter along the longitudinal direction. The negative coupling is realized by inserting additional off-resonant sites, which results in a four-band crossing point and helicoid surface states.
Three-dimensional (3D) semimetals with fourfold degenerate Dirac points are of prominent importance in topological photonics as the parent states to Weyl nodes, line nodes, & etc. The dispersions on all the momentums' directions are linear, which represents that the Dirac point and topologically protected helicoid surface states may exist. Here, we have demonstrated an acoustic metamaterial with Dirac points by designing the sign of coupling terms, specifically incorporating negative couplings. Tuning the coupling parameter along longitudinal direction, the transition from 3D Dirac point to Weyl points can be obtained. In realistic topological metamaterial designing, the negative coupling is realized by inserting additional off-resonant sites. The simulated band dispersion clearly shows four-band crossing point. The helicoid surface states are also proved. Our study provides a new approach of constructing 3D topological phase and shows the transition between nodal ring and Dirac point. Our results can be the theoretical basement of topological protected devices.
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