  The effect of microwave radiation on low-temperature electron
magnetotransport in a square antidot lattice with a period of d = 0.8
micrometer based on a GaAs quantum well with two occupied energy subbands E1
and E2 is investigated. It is shown that, owing to a significant difference
between the electron densities in the subbands, commensurability oscillations
of the resistance in the investigated antidot lattice are observed only for the
first subband. It is found that microwave irradiation under the cyclotron
resonance condition results in the formation of resistance oscillations
periodic in the inverse magnetic field in the region of the main
commensurability peak. It is established that the period of these oscillations
corresponds to the period of magneto-intersubband oscillations. The observed
effect is explained by the increase in the rate of intersubband scattering
caused by the difference between the electron heating in the subbands E1 and
E2.
