Electrical and Optical Breakdown of the Quantum Hall Effect

The subjects of this work are the experimental investigations of optically and electrically induced dissipation in 2DES under QH conditions and the numerical investigations of the dynamic conductivity and the equilibrium properties of 2DES subjected to THz radiation. The experiments are interesting because we investigate the single pulse shape of the 2DES response in the real-time domain. The numerical investigations could give a picture of the physics behind the THz interaction with 2DES. The electrical excitation is done by applying supercritical electrical pulses to the QH samples. The optical excitation is realized by applying simultaneously subcritical electrical pulses and THz radiation to the QH samples. The sample response is measured by a serial resistor and displayed on an digital oscilloscope. The photoresponse is given by the cyclotron resonance (CR) and the bolometric (BO) contributions. Especially, the BO contribution shows an interesting double-peak structure. By the numerical investigations we have found that the elevated electron temperature by THz radiation shows a double-peak structure at even filling factors for certain photon energies, as in the experiments.