  We report on the observation of the cyclotron-resonance-assisted photon drag
effect. Resonant photocurrent is detected in InSb/InAlSb quantum wells
structures subjected to a static magnetic field and excited by terahertz
radiation at oblique incidence. The developed theory based on Boltzmann's
kinetic equation is in a good agreement with the experimental findings. We show
that the resonant photocurrent originates from the transfer of photon momentum
to free electrons drastically enhanced at cyclotron resonance.
