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dc.contributor.authorKimme, Lukas
dc.contributor.authorHyart, Timo
dc.date.accessioned2016-06-20T10:32:11Z
dc.date.available2016-06-20T10:32:11Z
dc.date.issued2016
dc.identifier.citationKimme, L., & Hyart, T. (2016). Existence of zero-energy impurity states in different classes of topological insulators and superconductors and their relation to topological phase transitions. <i>Physical Review B</i>, <i>93</i>(3), Article 035134. <a href="https://doi.org/10.1103/PhysRevB.93.035134" target="_blank">https://doi.org/10.1103/PhysRevB.93.035134</a>
dc.identifier.otherCONVID_25570117
dc.identifier.otherTUTKAID_69302
dc.identifier.urihttps://jyx.jyu.fi/handle/123456789/50471
dc.description.abstractWe consider the effects of impurities on topological insulators and superconductors. We start by identifying the general conditions under which the eigenenergies of an arbitrary Hamiltonian H belonging to one of the Altland-Zirnbauer symmetry classes undergo a robust zero energy crossing as a function of an external parameter which can be, for example, the impurity strength. We define a generalized root of det H and use it to predict or rule out robust zero-energy crossings in all symmetry classes. We complement this result with an analysis based on almost degenerate perturbation theory, which allows a derivation of the asymptotic low-energy behavior of the ensemble averaged density of states ρ ∼ Eα for all symmetry classes and makes it transparent that the exponent α does not depend on the choice of the random matrix ensemble. Finally, we show that a lattice of impurities can drive a topologically trivial system into a nontrivial phase, and in particular we demonstrate that impurity bands carrying extremely large Chern numbers can appear in different symmetry classes of two-dimensional topological insulators and superconductors. We use the generalized root of det H(k) to reveal a spiderweblike momentum space structure of the energy gap closings that separate the topologically distinct phases in px + ipy superconductors in the presence of an impurity lattice.
dc.language.isoeng
dc.publisherAmerican Physical Society
dc.relation.ispartofseriesPhysical Review B
dc.subject.othertopological insulators
dc.subject.othertopological superconductors
dc.titleExistence of zero-energy impurity states in different classes of topological insulators and superconductors and their relation to topological phase transitions
dc.typearticle
dc.identifier.urnURN:NBN:fi:jyu-201606153091
dc.contributor.laitosFysiikan laitosfi
dc.contributor.laitosDepartment of Physicsen
dc.contributor.oppiaineNanoscience Centerfi
dc.contributor.oppiaineNanoscience Centeren
dc.type.urihttp://purl.org/eprint/type/JournalArticle
dc.date.updated2016-06-15T09:15:08Z
dc.type.coarjournal article
dc.description.reviewstatuspeerReviewed
dc.relation.issn1098-0121
dc.relation.numberinseries3
dc.relation.volume93
dc.type.versionpublishedVersion
dc.rights.copyright© 2016 American Physical Society. Published in this repository with the kind permission of the publisher.
dc.rights.accesslevelopenAccessfi
dc.subject.ysoepäpuhtaudet
jyx.subject.urihttp://www.yso.fi/onto/yso/p433
dc.relation.doi10.1103/PhysRevB.93.035134


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