Published April 16, 2019 | Version v2

Topological phases without crystalline counterparts

  • 1. QuTech and Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 4056, 2600 GA Delft, The Netherlands
  • 2. Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 4056, 2600 GA Delft, The Netherlands
  • 3. Microsoft Quantum, Microsoft Station Q, University of California, Santa Barbara, California 93106-6105
  • 4. IFW Dresden and W{\"u}rzburg-Dresden Cluster of Excellence ct.qmat, Helmholtzstr. 20, 01069 Dresden, Germany

Description

Topological phases without crystalline counterparts

We construct a higher-order topological phase protected by a point group symmetry that is impossible in any crystalline system. The tight-binding model describes a superconductor on a quasicrystalline Ammann–Beenker tiling which hosts localized Majorana zero modes at the corners of an octagonal sample. The Majorana modes are protected by particle-hole symmetry and by the combination of an 8-fold rotation and in-plane reflection symmetry. We find a bulk topological invariant associated with the presence of these zero modes, and show that they are robust against large symmetry preserving deformations, as long as the bulk remains gapped. The nontrivial bulk topology of this phase falls outside all currently known classification schemes.

Contents

  • Code to generate all figures in the manuscript: in octo_hoti.ipynb and octo_hoti_kpm.ipynb.

  • Data to generate large patches of the tiling.

  • Data produced by the longer calculations.

  • Code and results of symmetry analysis using Qsymm in symmetry_analysis.ipynb.

Requirements

  • kwant >= 1.4

  • qsymm >= 1.1

Files

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Additional details

Related works

Is supplement to
arXiv:1904.07242 (arXiv)

Funding

European Commission
STATOPINS - Theory of statistical topological insulators 638760