Observation of a topological nodal surface and its surface-state arcs in an artificial acoustic crystal.

Journal Article (Journal Article)

Three-dimensional (3D) gapless topological phases can be classified by the dimensionality of the band degeneracies, including zero-dimensional (0D) nodal points, one-dimensional (1D) nodal lines, and two-dimensional (2D) nodal surfaces. Both nodal points and nodal lines have been realized recently in photonics and acoustics. However, a nodal surface has never been observed in any classical-wave system. Here, we report on the experimental observation of a twofold symmetry-enforced nodal surface in a 3D chiral acoustic crystal. In particular, the demonstrated nodal surface carries a topological charge of 2, constituting the first realization of a higher-dimensional topologically-charged band degeneracy. Using direct acoustic field measurements, we observe the projected nodal surface and its Fermi-arc-like surface states and demonstrate topologically-induced robustness of the surface states against disorders. This discovery of a higher-dimensional topologically-charged band degeneracy paves the way toward further explorations of the physics and applications of new topological semimetal phases.

Full Text

Duke Authors

Cited Authors

  • Yang, Y; Xia, J-P; Sun, H-X; Ge, Y; Jia, D; Yuan, S-Q; Yang, SA; Chong, Y; Zhang, B

Published Date

  • November 15, 2019

Published In

Volume / Issue

  • 10 / 1

Start / End Page

  • 5185 -

PubMed ID

  • 31729392

Pubmed Central ID

  • PMC6858449

Electronic International Standard Serial Number (EISSN)

  • 2041-1723

International Standard Serial Number (ISSN)

  • 2041-1723

Digital Object Identifier (DOI)

  • 10.1038/s41467-019-13258-3

Language

  • eng