Scattering theory of delicate topological insulators

Penghao Zhu, Jiho Noh, Yingkai Liu, Taylor L. Hughes

Research output: Contribution to journalArticlepeer-review


We study the scattering theory of delicate topological insulators (TIs), which are novel topological phases beyond the paradigm of the tenfold way, topological quantum chemistry, and the symmetry indicator method. We demonstrate that the phase of the reflection amplitude can probe the delicate topology by capturing a characteristic feature of a delicate TI. This feature is the returning Thouless pump, where an integer number of charges are pumped forward and backward in the first and second half of the adiabatic cycle, respectively. As a by-product of our analysis we show that requiring additional symmetries can stable the boundary states of a delicate TI beyond the conventional requirement of a sharply defined surface. Furthermore, we propose a waveguide array experiment to implement a delicate TI and measure its reflection phase which reveals the delicate topology.

Original languageEnglish (US)
Article number195110
JournalPhysical Review B
Issue number19
StatePublished - May 15 2023
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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