A comparative study of the radiation-induced magnetoresistance oscillations
in the high mobility GaAs/AlGaAs heterostructure two dimensional electron
system (2DES) under linearly- and circularlypolarized microwave excitation
indicates a profound difference in the response observed upon rotating the
microwave launcher for the two cases, although circularly polarized microwave
radiation induced magnetoresistance oscillations observed at low magnetic
fields are similar to the oscillations observed with linearly polarized
radiation. For the linearly polarized radiation, the magnetoresistive response
is a strong sinusoidal function of the launcher rotation (or linear
polarization) angle, {\theta}. For circularly polarized radiation, the
oscillatory magnetoresistive response is hardly sensitive to {\theta}