Microwave strengths to induce magnetoresistance oscillations in   high-mobility 2DES in a photon-assisted impurity scattering model
  It is shown that, although the major feature of the microwave-induced magnetoresistance oscillations in two-dimensional (2D) electron systems is insensitive to the behavior of the elastic scattering in the photon-assisted impurity scattering model [X.L. Lei and S.Y. Liu, Phys. Rev. Lett. 91, 226805 (2003)], the required microwave intensity to induce an effective oscillation depends strongly on the form of the impurity potential. A microwave electric field of a few Volts per cm in amplitude is sufficient to induce remarkable oscillations if the elastic scatterings are due to background charged impurities, which is an order of magnitude smaller than that needed if the scatterings are due to remote charged impurities located 60 nm away from 2D electron gas. 
X.L. Lei