Berlin 2024 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 28: Topology: Other Topics
TT 28.5: Vortrag
Dienstag, 19. März 2024, 10:30–10:45, H 3025
Topological properties of a non-Hermitian quasi-1D chain with a flat band — •Carolina Martínez-Strasser1,2,3, Miguel Ángel J. Herrera1,2, Aitzol García-Etxarri2,4, Giandomenico Palumbo5, Flore K. Kunst3, and Dario Bercioux2,4 — 1Department of Physics, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain — 2Donostia International Physics Center (DIPC), 20018 Donostia–San Sebastián, Spain — 3Max Planck Institute for the Science of Light, Staudtstraße 2, 91058 Erlangen, Germany — 4IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5 48009 Bilbao, Spain — 5School of Theoretical Physics, Dublin Institute for Advanced Studies, 10 Burlington Road, Dublin 4, Ireland
We explore the spectral characteristics of a non-Hermitian quasi-1D lattice in two different dimerization configurations. The lattice exhibits a zero-energy flat band, and an accumulation of bulk eigenstates at the boundaries. Despite this behavior, we identify non-trivial edge states at zero energy for the first configuration through a real-space topological invariant called the biorthogonal polarization. For the second configuration, we analyze the finite quantum metric associated with the flat band. Interestingly, this configuration exhibits the skin effect, even though the system has a spectrum that is purely real or imaginary. Both non-Hermitian diamond chains can be mapped to models of Su-Schrieffer-Heeger chains, either non-Hermitian or Hermitian, both featuring a flat band. This mapping provides valuable insights into the system’s properties.