Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 30: Quantum dots and wires: Transport properties II

HL 30.6: Talk

Tuesday, February 26, 2008, 15:30–15:45, ER 164

Fermi-edge Singularity in 2D-0D Resonant Tunneling Through A Self-Assembled Quantum Dot — •Michael Rüth, Anatoliy Slobodskyy, Charles Gould, Georg Schmidt, and Laurens Molenkamp — Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074

We report on transport experiments on a single self-assembled CdSe quantum dot. In this sample, the zero-field signal displays clear resonant tunneling behavior, with a peak-to-valley ratio of 6.7 at T=1K. Moreover, the I/V-curve is clearly indicative of the occurrence of Fermi-edge singularity behavior in this system. No other resonance signal can be found within a range of 100mV, therefore we assume that only one quantum dot contributes to the tunneling transport in this voltage range. The effect shows high temperature stabilty, the peak current only decreases by a factor of 4 from 1K to 40K. For magnetic fields up to 16T, applied perpendicular to the surface, we observe multiple Landau level structures in the current-voltage characteristics, which provides evidence that the electrons in the ZnSe contact are confined to 2 dimensions. The maximum peak current occurs at B≈12T, a possible cause being a field enhanced FES [1].

[1] E.E. Vodin, Yu. N. Khanin, O.Makarovsky, Yu. V. Dubrovskii, A. Patanè, L. Eaves, M. Henini, C.J. Mellor, K.A. Benedict and R. Airey, Phys. Rev. B75, 115315 (2007)