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arXiv · 1902.01268

Transport signatures of symmetry protection in 1D Floquet topological insulators

Oleksandr Balabanov·Henrik Johannesson
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Abstract

Time-periodic external drives have emerged as a powerful tool to artificially create topological phases of matter. Prime examples are Floquet topological insulators (FTIs), where a gapped bulk supports in-gap edge states, protected against symmetry-preserving local perturbations. Similar to an ordinary static topological insulator, the robustness of an edge state in a one-dimensional (1D) FTI shows up as a pinning of its quasienergy level, but now inside one of two distinct bulk gaps. Here we propose a scheme for probing this unique feature by observing transport characteristics of a 1D finite-sized FTI attached to external leads. We present predictions for transmission spectra using a nonequilibrium Green's function approach. Our analysis covers FTIs with time-independent and periodically driven boundary perturbations which either preserve or break the protecting chiral symmetry.

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Oleksandr Balabanov, Henrik Johannesson. 2019-02-04. Transport signatures of symmetry protection in 1D Floquet topological insulators. https://doi.org/10.1088/1361-648x/ab4319

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