Multiple scattering theory of non-Hermitian sonic second-order topological insulators Articles uri icon

publication date

  • October 2019

start page

  • 1

end page

  • 7

volume

  • 2, 132

International Standard Serial Number (ISSN)

  • 2399-3650

abstract

  • Topological phases of sound enable unconventional confinement of acoustic energy at the corners in higher-order topological insulators. These unique states which go beyond the conventional bulk-boundary correspondence have recently been extended to non-Hermitian wave physics comprising finite crystal structures including loss and gain units. We use a multiple scattering theory to calculate these topologically trapped complex states that agree very well to finite element predictions. Moreover, our semi-numerical tool allows us to compute the spectral dependence of corner states in the presence of defects, illustrating the limits of the topological resilience of these confined non-Hermitian acoustic states.

keywords

  • applied physics; condensed-matter physics