Edge states manifestation in non-Hermitian topological systems

Project Director: Dr. Bogdan Ostahie

Project ID: PN-III-P1-1.1-PD-2019-0595

Project Director: Dr. Ostahie Bogdan

Project Type: National Project Program PD

Funded by: Romanian National Authority for Scientific Research, UEFISCDI

Contractor: National Institute of Materials Physics

Project Status: In progress

Start Date: 24.08.2020

End Date: 23.07.2022

Project Title: Edge states manifestation in non-Hermitian topological systems

Project Abstract: The proposed project investigates the spectral and transport properties in open topological systems. The open systems will consist in finite lattices to which several semi-infinite leads are attached and the resulting systems are described by an effective Hamiltonian, which is non-Hermitian. The complex energy spectrum will be analyzed at different parameters: coupling between the lattice and semi-infinite leads, impurities and lattice distortion. The aim is to show how the edge states, in the topological phase, are influence by the external environment in one and two dimensional systems. The role of disorder will be investigated using the random matrix theory. Moreover, one of the fundamental reasons is to show the correspondences between localization and spectral statistic in non-Hermitian topological systems. The quantum transport properties will be studied employing the Landauer-Büttiker formalism. In the one dimensional case the goal is to analytically calculate the transmission coefficient for the topological edge states. Additionally, the effect of the coupling with the leads of the states localized at the edge will be analyzed, emphasizing the robustness of the edge states in one dimensional systems in the topological phase with open boundaries. In two dimensional non-Hermitian topological systems it is expected that the quantum Hall phase to be richer because of the mixing between anomalous and chiral edge states. Furthermore, it is expected that the disorder will induce the appearance of a new type of topological Anderson insulator.

Dr. Ostahie Bogdan  - Project Director

Dr. Catalin Pascu Moca  - Mentor

B. Ostahie and A. Aldea ”Spectral analysis, chiral disorder and topological edge states manifestation in open non-Hermitian Su-Schrieffer-Heeger chains” Physics Letters A 387 (2021) 127030


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