The microwave-induced resistance oscillations and “zero-resistance” states were discovered in ultraclean two-dimensional electron systems in 2001–2003 and have attracted great interest from researchers. A comprehensive theory of these phenomena was developed in 2011: It was shown that all experimentally observed dependencies can be naturally explained by the influence of the ponderomotive forces which arise in the near-contact regions of the two-dimensional electron gas under the action of microwaves. Now, we show that the same near-contact physical processes should lead to another nonlinear electrodynamic phenomenon: the second-harmonic generation. We calculate the frequency, magnetic field, mobility, and power dependencies of the second-harmonic intensity and show that it can be as large as $\gtrsim 0.5$ mW/cm${}^2$ under realistic experimental conditions. A part of this paper is devoted to a further development of the ponderomotive-force theory: we show how it explains different experimental details, including those which were not known in 2011.

• Received 11 May 2013
• Revised 5 December 2013

DOI:https://doi.org/10.1103/PhysRevB.89.045410