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HL: Fachverband Halbleiterphysik

HL 30: Quantum dots and wires: Transport properties II

HL 30.9: Vortrag

Dienstag, 26. Februar 2008, 16:30–16:45, ER 164

Electron counting statistic on a triple dot device — •Christian Fricke¹, Maximilian Rogge¹, Frank Hohls¹, Werner Wegscheider², and Rolf Haug¹ — ¹Institut für Festkörperphysik, Leibniz Universität Hannover — ²Angewandte und Experimentelle Physik, Universität Regensburg

Current fluctuations in mesoscopic conductors can be used to reveal information which is not accessible through dc conductance measurements. Combining the mean current with the second moment of the distribution function the zero frequency shot noise can provide an insight into tunnelling rates in semiconductor quantum dots. Beside a direct measurement of the resonant tunnelling current through a quantum dot one can measure also the charge on the quantum dot using a nearby quantum point contact. For sufficiently low tunnelling rates and high detector bandwidth this allows to resolve individual tunnelling events onto and off the dot. This technique was used to measure the distribution function for tunnelling through a single [1,2] and double quantum dot [3]. We present first measurements on a system of three dots. One quantum point contact is used as a charge detector. The time resolved current through the quantum point contact is measured and analyzed.

[1]Gustavsson et al. Phys. Rev. Lett. 96, 076605 (2006)

[2]Fricke et al. Phys. Rev. B 76, 155307 (2007)

[3]Fujisawa et al. Science 312, 1634 (2006)