Electron localization and optical absorption of polygonal quantum rings

• Published in: Physical Review B
• Main Authors: Sitek, Anna, Serra, Llorenç, Gudmundsson, Vidar, Manolescu, Andrei
• Other Authors: Ministerio de Economía y Competitividad (España), University of Iceland
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Physical Society 2015
• Subjects: Iceland
• Online Access: http://hdl.handle.net/10261/132894; https://doi.org/10.1103/PhysRevB.91.235429; https://doi.org/10.13039/501100003329

© 2015 American Physical Society. We investigate theoretically polygonal quantum rings and focus mostly on the triangular geometry where the corner effects are maximal. Such rings can be seen as short core-shell nanowires, a generation of semiconductor heterostructures with multiple applications. We show how the geometry of the sample determines the electronic energy spectrum, and also the localization of electrons, with effects on the optical absorption. In particular, we show that irrespective of the ring shape low-energy electrons are always attracted by corners and are localized in their vicinity. The absorption spectrum in the presence of a magnetic field shows only two peaks within the corner-localized state domain, each associated with different circular polarization. This picture may be changed by an external electric field which allows previously forbidden transitions, and thus enables the number of corners to be determined. We show that polygonal quantum rings allow absorption of waves from distant ranges of the electromagnetic spectrum within one sample. This work was financially supported by the Research Fund of the University of Iceland, the Nordic network NANOCONTROL, project No.: P-13053, and by MINECO-Spain (Grant No. FIS2011-23526). Peer Reviewed