Dynamical Chiral Symmetry and Symmetry-Class Conversion in Floquet Topological Insulators

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Auteurs principaux: Assili, Mohamed, Kotetes, Panagiotis
Format: Preprint
Publié: 2024
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author Assili, Mohamed
Kotetes, Panagiotis
author_facet Assili, Mohamed
Kotetes, Panagiotis
contents In this work, we discuss properties with no static counterpart arising in Floquet topological insulators with a dynamical chiral symmetry (DCS), i.e., a chiral symmetry which is present while driving. We explore the topological properties of Floquet insulators possessing a DCS which either does or does not survive upon taking the static limit. We consider the case of harmonic drives and employ a general framework using the quasi-energy operator in frequency space. We find that for a DCS with no static analog, the presence of driving has a negligible impact on the topological phases associated with zero quasi-energy. In stark contrast, topological gaps can open at $π$ quasi-energy and mainly occur at momenta where the driving perturbation vanishes. We confirm the above general predictions for an extended Kitaev chain model in the BDI symmetry class. Another possibility that opens up when adding the drive, while preserving chiral symmetry, is symmetry-class conversion. We demonstrate such an effect for a static CI class Hamiltonian which is topologically trivial in 1D. By considering a suitable driving, we obtain a CI$\rightarrow$AIII transition, which now enables the system to harbor topological $π$-modes. Notably, the arising topological phases strongly depend on whether the DCS has a static analog or not. Our results bring Floquet insulators with nonstandard DCS forward as ideal candidate platforms for engineering and manipulating topological $π$-modes.
format Preprint
id arxiv_https___arxiv_org_abs_2401_05697
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Dynamical Chiral Symmetry and Symmetry-Class Conversion in Floquet Topological Insulators
Assili, Mohamed
Kotetes, Panagiotis
Mesoscale and Nanoscale Physics
Materials Science
Superconductivity
Quantum Physics
In this work, we discuss properties with no static counterpart arising in Floquet topological insulators with a dynamical chiral symmetry (DCS), i.e., a chiral symmetry which is present while driving. We explore the topological properties of Floquet insulators possessing a DCS which either does or does not survive upon taking the static limit. We consider the case of harmonic drives and employ a general framework using the quasi-energy operator in frequency space. We find that for a DCS with no static analog, the presence of driving has a negligible impact on the topological phases associated with zero quasi-energy. In stark contrast, topological gaps can open at $π$ quasi-energy and mainly occur at momenta where the driving perturbation vanishes. We confirm the above general predictions for an extended Kitaev chain model in the BDI symmetry class. Another possibility that opens up when adding the drive, while preserving chiral symmetry, is symmetry-class conversion. We demonstrate such an effect for a static CI class Hamiltonian which is topologically trivial in 1D. By considering a suitable driving, we obtain a CI$\rightarrow$AIII transition, which now enables the system to harbor topological $π$-modes. Notably, the arising topological phases strongly depend on whether the DCS has a static analog or not. Our results bring Floquet insulators with nonstandard DCS forward as ideal candidate platforms for engineering and manipulating topological $π$-modes.
title Dynamical Chiral Symmetry and Symmetry-Class Conversion in Floquet Topological Insulators
topic Mesoscale and Nanoscale Physics
Materials Science
Superconductivity
Quantum Physics
url https://arxiv.org/abs/2401.05697