Amorphous topological phases protected by continuous rotation symmetry
Helene Spring, Anton R. Akhmerov, Daniel Varjas
SciPost Phys. 11, 022 (2021) · published 5 August 2021
- doi: 10.21468/SciPostPhys.11.2.022
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Abstract
Protection of topological surface states by reflection symmetry breaks down when the boundary of the sample is misaligned with one of the high symmetry planes of the crystal. We demonstrate that this limitation is removed in amorphous topological materials, where the Hamiltonian is invariant on average under reflection over any axis due to continuous rotation symmetry. While the local disorder caused by the amorphous structure weakens the topological protection, we demonstrate that the edge remains protected from localization. In order to classify such phases we perform a systematic search over all the possible symmetry classes in two dimensions and construct the example models realizing each of the proposed topological phases. Finally, we compute the topological invariant of these phases as an integral along a meridian of the spherical Brillouin zone of an amorphous Hamiltonian.
Cited by 21
Authors / Affiliations: mappings to Contributors and Organizations
See all Organizations.- 1 Helene Spring,
- 1 Anton R. Akhmerov,
- 1 2 Daniel Varjas
- 1 Technische Universiteit Delft / Delft University of Technology [TU Delft]
- 2 Stockholm University [Univ Stockholm]