Superlattices and Microstructures 48 (2010) 491–501 Contents lists available at ScienceDirect Superlattices and Microstructures journal homepage: www.elsevier.com/locate/superlattices Electron and hole states in a quantum ring grown by droplet epitaxy: Influence of the layer inside the ring opening N. Čukarić a,b , M. Tadić a,∗ , F.M. Peeters b a Faculty of Electrical Engineering, University of Belgrade, P.O. Box 3554, 11120 Belgrade, Serbia b Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium article info Article history: Received 30 April 2010 Received in revised form 9 August 2010 Accepted 3 September 2010 Available online 21 September 2010 Keywords: Quantum ring Quantum dot Nanoring Nanodot Luttinger–Kohn Multiband Band mixing abstract The electronic structure of the conduction and valence bands of a quantum ring containing a layer inside the ring opening is modeled. This structure (nanocup) consists of a GaAs nanodisk (the cup’s bottom) and a GaAs nanoring (the cup’s rim) which encircles the disk. The whole system is embedded in an (Al,Ga)As matrix, and its shape resembles realistic ring structures grown by the droplet epitaxy technique. The conduction-band states in the structure are modeled by the single-band effective-mass theory, while the 4-band Luttinger–Kohn model is adopted to compute the valence-band states. We analyze how the electronic structure of the nanocup evolves from the one of a quantum ring when the size of either the nanodisk or the nanoring is changed. For that purpose, (1) the width of the ring, (2) the disk radius, and (3) the disk height are separately varied. For dimensions typical for experimentally realized structures, we find that the electron wavefunctions are mainly localized inside the ring, even when the thickness of the inner layer is 90% of the ring thickness. These calculations indicate that topological phenomena, like the excitonic Aharonov–Bohm effect, are negligibly affected by the presence of the layer inside the ring. © 2010 Elsevier Ltd. All rights reserved. ∗ Corresponding author. Tel.: +381 11 3370 088. E-mail addresses: nemanja.cukaric@etf.bg.ac.rs (N. Čukarić), milan.tadic@etf.bg.ac.rs (M. Tadić), francois.peeters@ua.ac.be (F.M. Peeters). 0749-6036/$ – see front matter © 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.spmi.2010.09.001