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PT phase transitions of edge states at PT symmetric interfaces in non-Hermitian topological insulators

Ni, Xiang; Smirnova, Daria; Poddubny, Alexander; Leykam, Daniel; Chong, Yidong; Khanikaev, Alexander B.

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We demonstrate that the parity-time (PT) symmetric interfaces formed between non-Hermitian amplifying (“gainy”) and lossy topological crystals exhibit PT phase transitions separating phases of lossless and decaying/amplifying topological edge transport. The spectrum of these interface states exhibits exceptional points (EPs) separating (i) a PT symmetric real-valued regime with an evenly distributed wave function in both gainy and lossy domains and (ii) a PT broken complex-valued regime, in...[Show more]

dc.contributor.authorNi, Xiang
dc.contributor.authorSmirnova, Daria
dc.contributor.authorPoddubny, Alexander
dc.contributor.authorLeykam, Daniel
dc.contributor.authorChong, Yidong
dc.contributor.authorKhanikaev, Alexander B.
dc.date.accessioned2020-04-07T01:33:56Z
dc.date.available2020-04-07T01:33:56Z
dc.identifier.issn2469-9950
dc.identifier.urihttp://hdl.handle.net/1885/202781
dc.description.abstractWe demonstrate that the parity-time (PT) symmetric interfaces formed between non-Hermitian amplifying (“gainy”) and lossy topological crystals exhibit PT phase transitions separating phases of lossless and decaying/amplifying topological edge transport. The spectrum of these interface states exhibits exceptional points (EPs) separating (i) a PT symmetric real-valued regime with an evenly distributed wave function in both gainy and lossy domains and (ii) a PT broken complex-valued regime, in which edge states asymmetrically localize in one of the domains. Despite its complex-valued character, the edge spectrum remains gapless and connects complex-valued bulk bands through the EPs. We find that the regimes exist when the real edge spectrum is embedded into the bulk continuum without mixing, indicating that the edge states are protected against leakage into the bulk by the PT symmetry. Two exemplary PT symmetric systems, exhibiting valley and Chern topological phases, respectively, are investigated and the connection with the corresponding Hermitian systems is established. Interestingly, despite the complex bulk spectrum of the Chern insulator, the bulk-interface correspondence principle still holds, as long as the topological gap remains open. The proposed systems are experimentally feasible in photonics, which is evidenced by our rigorous full-wave simulations of PT symmetric silicon-based photonic graphene.
dc.description.sponsorshipThe authors gratefully acknowledge financial support from the National Science Foundation Grants No. DMR-1809915 and No. EFRI-1641069. D.S. was supported by the Russian Foundation for Basic Research (Grant No. 18-02-00381). A.N.P. acknowledges support by the Australian Research Council and the Foundation for the Advancement of Theoretical Physics and Mathematics “Basis”. Y.D.C. acknowledges support by the Singapore MOE Academic Research Fund Tier 3 Grant MOE2016-T3-1-006.
dc.format.mimetypeapplication/pdf
dc.language.isoen_AU
dc.publisherAmerican Physical Society
dc.rights© 2018 American Physical Society
dc.sourcePhysical Review B
dc.titlePT phase transitions of edge states at PT symmetric interfaces in non-Hermitian topological insulators
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume98
dc.date.issued2018
local.identifier.absfor020503 - Nonlinear Optics and Spectroscopy
local.identifier.ariespublicationu4485658xPUB1363
local.publisher.urlhttps://www.aps.org/
local.type.statusPublished Version
local.contributor.affiliationNi, Xiang, City University of New York
local.contributor.affiliationSmirnova, Daria, College of Science, ANU
local.contributor.affiliationPoddubny, Alexander, College of Science, ANU
local.contributor.affiliationLeykam, Daniel, Nanyang Technological University
local.contributor.affiliationChong, Yidong, Nanyang Technological University
local.contributor.affiliationKhanikaev, Alexander B., University of New York
local.bibliographicCitation.issue165129
local.bibliographicCitation.startpage1
local.bibliographicCitation.lastpage13
local.identifier.doi10.1103/PhysRevB.98.165129
local.identifier.absseo970102 - Expanding Knowledge in the Physical Sciences
dc.date.updated2019-11-25T07:51:12Z
local.identifier.scopusID2-s2.0-85055122134
dcterms.accessRightsOpen Access
dc.provenancehttp://sherpa.ac.uk/romeo/issn/2469-9950/..."author can archive publisher's version/PDF" from Sherpa/Romeo as at 7/04/2020. Ni, Xiang, et al. "PT phase transitions of edge states at PT symmetric interfaces in non-Hermitian topological insulators." Physical Review B 98.16 (2018): 165129.
CollectionsANU Research Publications

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