We study non-linear transport phenomena in a high-mobility bilayer system
with two closely spaced populated electronic subbands in a perpendicular
magnetic field. For a moderate direct current excitation, we observe
zero-differential-resistance states with a characteristic 1/B periodicity. We
investigate, both experimentally and theoretically, the Hall field-induced
resistance oscillations which modulate the high-frequency magneto-intersubband
oscillations in our system if we increase the current. We also observe and
describe the influence of direct current on the magnetoresistance in the
presence of microwave irradiation.Comment: 8 pages, 6 figure
