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Non-Hermitian semi-Dirac semi-metals

Banerjee, A and Narayan, A (2021) Non-Hermitian semi-Dirac semi-metals. In: Journal of Physics Condensed Matter, 33 (22).

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Official URL: https://doi.org/10.1088/1361-648X/abe796


Recently, many novel and exotic phases have been proposed by considering the role of topology in non-Hermitian systems, and their emergent properties are of wide current interest. In this work we propose the non-Hermitian generalization of semi-Dirac semimetals, which feature a linear dispersion along one momentum direction and a quadratic one along the other. We study the topological phase transitions in such two-dimensional semi-Dirac semimetals in the presence of a particle gain-and-loss term. We show that such a non-Hermitian term creates exceptional points (EPs) originating out of each semi-Dirac point. We map out the topological phase diagram of our model, using winding number and vorticity as topological invariants of the system. By means of numerical and analytical calculations, we examine the nature of edge states for different types of semi-Dirac models and establish bulk-boundary correspondence and absence of the non-Hermitian skin effect, in one class. On the other hand, for other classes of semi-Dirac models with asymmetric hopping, we restore the non-Hermitian skin effect, an anomalous feature usually present in non-Hermitian topological systems. © 2021 IOP Publishing Ltd.

Item Type: Journal Article
Publication: Journal of Physics Condensed Matter
Publisher: IOP Publishing Ltd
Additional Information: The copyright for this article belongs to Authors
Keywords: Phase diagrams; Skin effect, Analytical calculation; Emergent property; Exceptional points; Linear dispersion; Momentum direction; Topological invariants; Topological phase; Topological systems, Topology
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited: 03 Aug 2021 07:50
Last Modified: 03 Aug 2021 07:50
URI: http://eprints.iisc.ac.in/id/eprint/68917

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