Berlin 2015 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 60: Quantum dots: Transport
HL 60.1: Talk
Wednesday, March 18, 2015, 17:15–17:30, EW 203
The Kondo resonance of a quantum dot in magnetic fields — •Alexander W. Heine1, Daniel Tutuc1, Gertrud Zwicknagl2, and Rolf J. Haug1 — 1Institut für Festkörperphysik, Leibniz Universität Hannover, 30167 Hannover, Germany — 2Institut für Mathematische Physik, Technische Universität Braunschweig, 38106 Braunschweig, Germany
The fingerprint of the Kondo effect in quantum dots is a peak of enhanced conductance at zero bias, the so-called zero bias anomaly. We examine experimentally the influence of magnetic fields on this zero bias peak. The measurements were performed in an 3He/4He dilution refrigerator with a base temperature of about 20 mK. A magnetic field B up to 6 T was applied parallel as well as perpendicular to the sample surface.
In a perpendicular magnetic field we analyze the splitting of the Kondo resonance in the so-called Kondo chessboard. Here a decrease of the splitting width with increasing magnetic field is observed. The data is compared to numerical renormalization group calculations by Hewson et al.[1], which show the relation between the effective splitting of the zero bias anomaly and B/TK. Thereby we can show, that the quantum Hall effect in the two-dimensional leads affects the Kondo temperature and therefore the splitting of the zero bias anomaly.
[1] Hewson et al., Phys. Rev. B 73, 045117 (2006)