Photovoltaic oscillations due to edge-magnetoplasmon modes in a very high-mobility two-dimensional electron gas

Using very high-mobility GaAs/Al(x)Ga(1-x)As two-dimensional electron Hall bar samples, we have experimentally studied the photoresistance and/or photovoltaic oscillations induced by microwave irradiation in the regime where both 1/B and B-periodic oscillations can be observed. In the frequency range between 27 and 130 GHz, we found that these two types of oscillations are decoupled from each other, consistent with the respective models that 1/B oscillations occur in bulk while the B oscillations occur along the edges of the Hall bars. In contrast to the original report of this phenomenon [I. V. Kukushkin , Phys. Rev. Lett. 92, 236803 (2004)], the periodicity of the B oscillations in our samples is found to be independent of L, the length of the Hall bar section between voltage measuring leads.