Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP

@article{Peng2021DegenerateTL,
  title={Degenerate topological line surface phonons in quasi-1D double helix crystal SnIP},
  author={Bo Peng and Shuichi Murakami and Bartomeu Monserrat and Tiantian Zhang},
  journal={npj Computational Materials},
  year={2021},
  volume={7},
  pages={1-8}
}
Degenerate points/lines in the band structures of crystals have become a staple of the growing number of topological materials. The bulk-boundary correspondence provides a relation between bulk topology and surface states. While line degeneracies of bulk excitations have been extensively characterised, line degeneracies of surface states are not well understood. We show that SnIP, a quasi-one-dimensional van der Waals material with a double helix crystal structure, exhibits topological nodal… 
3 Citations
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TLDR
It is shown that multi-gap topologies and the accompanying phase transitions driven by braiding processes can be readily observed in the bosonic phonon spectra of known monolayer silicates, and it is proposed that the band inversion processes at the Γ point can be tracked by following the evolution of the Raman spectrum, providing clear signatures for experimental verification.
Phonons as a platform for multi-gap topology and non-Abelian braiding: A case study of layered silicates
Topological phases of matter have revolutionised the fundamental understanding of band theory and hold great promise for next-generation technologies such as low-power electronics or quantum
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Bo Peng, ∗ Adrien Bouhon, ∗ Robert-Jan Slager, † and Bartomeu Monserrat 3, † TCM Group, Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom Nordic

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