title: In-gap corner states in core-shell polygonal quantum rings.
abstract: We study Coulomb interacting electrons confined in polygonal quantum rings. We focus on the interplay of localization at the polygon corners and Coulomb repulsion. Remarkably, the Coulomb repulsion allows the formation of in-gap states, i.e., corner-localized states of electron pairs or clusters shifted to energies that were forbidden for non-interacting electrons, but below the energies of corner-side-localized states. We specify conditions allowing optical excitation to those states.
authors.affiliation: Science Institute, University of Iceland, Reykjavik, IS-107, Iceland.|School of Science and Engineering, Reykjavik University, Reykjavik, IS-101, Iceland.|Department of Theoretical Physics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wroclaw, 50-370, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Sitek
authors.affiliation: National Institute of Materials Physics, Bucharest-Magurele, P.O. Box MG-7, Romania.
authors.forename: Mugurel
authors.initials: M
authors.lastname: Ţolea
authors.affiliation: National Institute of Materials Physics, Bucharest-Magurele, P.O. Box MG-7, Romania.
authors.forename: Marian
authors.initials: M
authors.lastname: Niţă
authors.affiliation: Institute of Interdisciplinary Physics and Complex Systems IFISC (CSIC-UIB), Palma de Mallorca, E-07122, Spain.|Department of Physics, University of the Balearic Islands, Palma de Mallorca, E-07122, Spain.
authors.forename: Llorenç
authors.initials: L
authors.lastname: Serra
authors.affiliation: Science Institute, University of Iceland, Reykjavik, IS-107, Iceland.
authors.forename: Vidar
authors.initials: V
authors.lastname: Gudmundsson
authors.affiliation: School of Science and Engineering, Reykjavik University, Reykjavik, IS-101, Iceland.
authors.forename: Andrei
authors.initials: A
authors.lastname: Manolescu