Symmetry-protected topological invariant and Majorana impurity states in time-reversal-invariant superconductors

Lukas Kimme; Timo Hyart; Bernd Rosenow

doi:10.1103/physrevb.91.220501

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arXiv · 1308.2496

Symmetry-protected topological invariant and Majorana impurity states in time-reversal-invariant superconductors

Lukas Kimme·Timo Hyart·Bernd Rosenow

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Abstract

We address the question of whether individual nonmagnetic impurities can induce zero-energy states in time-reversal-invariant topological superconductors, and define a class of symmetries which guarantee the existence of such states for a specific value of the impurity strength. These symmetries allow the definition of a position-space topological Z_2 invariant, which is related to the standard bulk topological Z_2 invariant. Our general results are applied to the time-reversal-invariant p-wave phase of the doped Kitaev-Heisenberg model, where we demonstrate how a lattice of impurities can drive a topologically trivial system into the nontrivial phase.

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Lukas Kimme, Timo Hyart, Bernd Rosenow. 2015-06-02. Symmetry-protected topological invariant and Majorana impurity states in time-reversal-invariant superconductors. https://doi.org/10.1103/physrevb.91.220501

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