Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 28: Transport in high magnetic field/Quantum Hall-effect

HL 28.1: Talk

Wednesday, March 29, 2006, 16:30–16:45, HSZ 01

Electron interference and single electron charging in electronic Mach-Zehnder interferometer — •Leonid Litvin, Thomas Geiger, Peter Tranitz, Werner Wegscheider, and Cristoph Strunk — Institute for Experimental and Applied Physics; University of Regensburg, D-93040 Regensburg, Germany

Mach-Zehnder interferometer is promising device for two beam experiments with electrons in the integer quantum Hall regime where the electron flow is confined to a few edge states [1]. The effective path length and thus the phase accumulated along the edge states can be tuned by external magnetic field and a gate electrode. We have prepared Mach-Zehnder interferometers using high mobility GaAs/AlGaAs heterostructures and found two types of oscillation in current through the device as function of gate voltage: Aharonov-Bohm oscillations and smaller oscillation with six times smaller period. The small period oscillation show a beating pattern indicating two underlying frequencies, which correspond to the presence of two edge states (v=2) in the interferometer. From the temperature dependence of the small oscillation amplitude we infer a characteristic energy scale of 17*10^(-6) eV, which is in reasonable agreement with the charging energy of the interferometer. This points towards single electron charging as the origin of the additional small period oscillation. [1] Yang Ji et al., Nature 422, 415 (2003)