High sensitivity far-infrared detection by resonant inter-Landau-level scattering

The far-infrared (FIR) photoconductivity (PC) of a two-dimensional electron gas in the quantum Hall regime is investigated. We use a novel sample structure which is topologically equivalent to a Corbino-geometry; however, the circumference is greatly enlarged by a meander-like patterning. The geometry allows us to directly study the FIR-induced transport between edge states, which are separated by the insulating bulk region. Due to the high sensitivity of our sample structure it is possible to investigate the PC of our sample in a Fourier spectrometer using a broad band, black-body source with a very low spectral intensity compared to FIR-Lasers used in other experiments. Additionally, we present PC-measurements on a sample with gate tunable carrier density, which allows us to tune the resonance frequency.