Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 46: Quantum dots and wires: Preparation and characterization II

HL 46.2: Talk

Thursday, March 30, 2006, 15:30–15:45, POT 51

Observation of the Aharonov-Bohm effect in self-assembled nano-volcanoes — •V.M. Fomin^1,2,3, V.N. Gladilin^1,3, N.A.J.M. Kleemans², I.M.A. Bominaar-Silkens⁴, D. Granados⁵, J.M. García⁵, P. Offermans², U. Zeitler⁴, P.C.M. Christianen⁴, J.C. Maan⁴, J.T. Devreese^1,2, J.H. Wolter², and P.M. Koenraad² — ¹TFVS, Departement Fysica, Universiteit Antwerpen, B-2610 Antwerpen, Belgium — ²Department of Semiconductor Physics, TU Eindhoven, NL-5600 MB Eindhoven, The Netherlands — ³Department of Theoretical Physics, State University of Moldova, Kishinev, MD-2009, Moldova — ⁴HFML, Institute for Molecules and Materials, Radboud University Nijmegen, NL-6525 ED Nijmegen, The Netherlands — ⁵Instituto de Microelectrónica de Madrid, CSIC, E-28760 Madrid, Spain

Our X-STM data indicate that self-assembled InGaAs/GaAs nano-volcanoes are characterized by an asymmetric rim and a depression rather than an opening at the center. We show that these asymmetric singly connected structures still can effectively manifest the electronic properties, like the Aharonov-Bohm (AB) oscillations, peculiar to doubly connected geometry of ideal rings. AB oscillations in the persistent current are observed in low temperature magnetization measurements using the torsion magnetometry in magnetic fields up to 15 T and are in excellent agreement with theoretical predictions for strained nano-volcanoes. This work was been supported by the GOA BOF UA 2000, IUAP, FWO-V projects G.0274.01N, G.0435.03, the WOG WO.035.04N (Belgium), MCYT NANOSELF project (Spain) and the EC SANDiE Network of Excellence.