Anomalous topological edge states in non-Hermitian piezophononic media

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Show simple item record Gao, Penglin Willatzen, Morten Christensen, Johan 2020-12-10T12:40:24Z 2020-12-10T12:40:24Z 2020-11-13
dc.identifier.bibliographicCitation Physical Review Letters, (2020), 125(20), 206402, pp. 1-5.
dc.identifier.issn 0031-9007
dc.description.abstract The bulk-boundary or bulk-edge correspondence is a principle relating surface confined states to the topological classification of the bulk. By marrying non-Hermitian ingredients in terms of gain or loss with media that violate reciprocity, an unconventional non-Bloch bulk-boundary correspondence leads to unusual localization of bulk states at boundaries- a phenomenon coined non-Hermitian skin effect. Here, we numerically employ the acoustoelectric effect in electrically biased and layered piezophononic media as a solid framework for non-Hermitian and nonreciprocal topological mechanics in the MHz regime. Thanks to a non-Hermitian skin effect for mechanical vibrations, we find that the bulk bands of finite systems are highly sensitive to the type of crystal termination, which indicates a failure of using traditional Bloch bands to predict the wave characteristics. More surprisingly, when reversing the electrical bias, we unveil how topological edge and bulk vibrations can be harnessed either at the same or opposite interfaces. Yet, while bulk states are found to display this unconventional skin effect, we further discuss how in-gap edge states in the same instant, counterintuitively are able to delocalize along the entire layered medium. We foresee that our predictions will stimulate new avenues in echo-less ultrasonics based on exotic wave physics.
dc.description.sponsorship J. C. acknowledges support from the European Research Council (ERC) through the Starting Grant No. 714577 PHONOMETA and from the MINECO through a Ramón y Cajal grant (Grant No. RYC-2015-17156).
dc.format.extent 5
dc.language.iso eng
dc.publisher American Physical Society
dc.rights © 2020 American Physical Society.
dc.subject.other Topological phase transition
dc.subject.other Topological insulators
dc.title Anomalous topological edge states in non-Hermitian piezophononic media
dc.type article
dc.description.status Publicado
dc.subject.eciencia Física
dc.rights.accessRights openAccess
dc.relation.projectID info:eu-repo/grantAgreement/EC/H2020/714577/PHONOMETA
dc.relation.projectID Gobierno de España. RYC2015-17156
dc.type.version publishedVersion
dc.identifier.publicationfirstpage 1
dc.identifier.publicationissue 20, 206402
dc.identifier.publicationlastpage 5
dc.identifier.publicationtitle PHYSICAL REVIEW LETTERS
dc.identifier.publicationvolume 125
dc.identifier.uxxi AR/0000026425
dc.contributor.funder Ministerio de Economía y Competitividad (España)
dc.contributor.funder European Commission
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