Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 102: Quantum dots and wires: Transport

HL 102.3: Vortrag

Freitag, 15. März 2013, 11:45–12:00, H13

Magnetically induced quantized electron transport through localized magnetic fields in a quantum point contact — •Bernd Schüler, Mihai Cerchez, Hengyi Xu, and Thomas Heinzel — Heinrich Heine University Düsseldorf, Condensed Matter Laboratory, Universitätsstr. 1, 40225 Düsseldorf, Germany

Quantum Dots (QD) in two-dimensional electron gases are typically defined by nano-patterned gate electrodes [1]. While magnetically confined QDs have been proposed theoretically to show some specific phenomena [2], their experimental implementation is still at an early stage [3]. We have designed a ferromagnet/semiconductor hybrid structure device which allows us to form a QD by combining electrostatic potentials with localized magnetic fields in the form of two magnetic spikes at sub-micron distances. While numerical simulations of this system predict Coulomb blockade in the closed regime and Fano type resonances in the open system [4], we observe experimentally transmission resonances in the open system which can be interpreted as signatures of zero-dimensional states weakly bound by the magnetic field profile.

[1] see, e.g., L. P. Kouwenhoven et al., in Mesoscopic Electron Transport, Series E: Applied Sciences (Eds. L. L. Sohn, L. P. Kouwenhoven and G. Schon (Kluwer, 1997). [2] S.J. Lee et al., Phys. Rep. 394, 1, 2004 [3] A. Tarasov et al., Phys. Rev. Lett. 104, 186801, 2010 [4] H. Xu et al. Phys. Rev. B 84, 035319, 2011