Regensburg 2022 – scientific programme

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MA: Fachverband Magnetismus

MA 35: Poster 2

MA 35.75: Poster

Thursday, September 8, 2022, 16:00–18:00, P4

Topology and DC quantum transport in Floquet-driven systems — •Aya Abouelela and Johannes Kroha — University of Bonn

Recently, several works have investigated the topological properties emerging in periodically driven systems, where a periodic drive is used to engineer the band structure such as to support topologically stabilized edge modes. The topological phases of periodically driven systems have been classified across all dimensions in the periodic table of Floquet topological insulators. The Floquet multiplicity of bands implies the emergence of anomalous edge states which cross bulk gaps that do not occur in static systems. Here, we present our studies on the non-interacting topological Qi-Wu-Zhang (QWZ) model under the influence of a periodic drive, and analyze its drive-induced edge modes, using the Floquet formalism. Investigating two regimes of the driving frequency , higher or lower than the static bandwidth, the latter is shown to support anomalous edge modes. For the experimental detection of edge states, we calculate the dI/dV spectra at non-zero DC bias voltage V, using the Keldysh-Floquet formalism. We predict quantized conductance plateaus when the transport voltage is within a normal gap (V centered around V = 0, normal edge mode) or within an anomalous gap (V centered around V = ±Ω/2, anomalous edge mode). We also perfom a spatially resolved computation of the chiral tranmission channels of the finite- size system with finite bias applied, showing that the transport is along an edge and that it is spatially modulated corresponding to the wave number π of the (anomalous) edge mode.