Edge induced magneto plasmon excitation in a two-dimensional electron gas under quantum Hall conditions

The spectrally resolved Terahertz photoconductivity between two separately contacted edge-channels of a two-dimensional electron gas in the quantum Hall regime is investigated. We use a not-simply-connected sample geometry which is topologically equivalent to a Corbino disc. Due to the high sensitivity of our novel sample structure, a weak resonance situated on the high energy side of the well known cyclotron resonance is revealed. The magnetic field as well as the carrier density dependence of this weak resonance, in comparison with different models suggests that the additional resonance is an edge induced magneto plasmon, which has so far not been observed in semiconductors.