Study of the angular phase shift in the polarization angle dependence of the microwave induced magnetoresistance oscillations

We examine the microwave frequency($f)$-variation of the angular-phase-shift, $\theta_{0}$, observed in the polarization-angle-dependence of the microwave-induced magnetoresistance oscillations in the high mobility GaAs/AlGaAs two-dimensional electron system[1][2]. By fitting the diagonal resistance R$_{xx}$ vs. $\theta_{0}$ plots to an empirical cosine square law, we extract the $\theta_{0}$ and trace its quasi-continuous variation with $f$. The results suggest that the overall average of $\theta_{0}$ extracted from Hall bar device sections with length-to-width ratio L/W $=$ 1 and L/W $=$ 2 is the same. We compare the observations with expectations arising from the ``pondermotive force'' theory for the microwave radiation-induced transport phenomena. [1] R. G. Mani et al., Phys. Rev. B 84, 085308 (2011). [2] A. N. Ramanayaka et al., Phys. Rev. B 85, 205315 (2012).