  The effect of a microwave field in the frequency range from 54 to 140
$\mathrm{GHz}$ on the magnetotransport in a GaAs quantum well with AlAs/GaAs
superlattice barriers and with an electron mobility no higher than $10^6$
$\mathrm{cm^2/Vs}$ is investigated. In the given two-dimensional system under
the effect of microwave radiation, giant resistance oscillations are observed
with their positions in magnetic field being determined by the ratio of the
radiation frequency to the cyclotron frequency. Earlier, such oscillations had
only been observed in GaAs/AlGaAs heterostructures with much higher mobilities.
When the samples under study are irradiated with a 140-$\mathrm{GHz}$ microwave
field, the resistance corresponding to the main oscillation minimum, which
occurs near the cyclotron resonance, appears to be close to zero. The results
of the study suggest that a mobility value lower than $10^6$ $\mathrm{cm^2/Vs}$
does not prevent the formation of zero-resistance states in magnetic field in a
two-dimensional system under the effect of microwave radiation.

Mesoscale and Nanoscale Physics