Current-pinch effect in inhomogeneous two-dimensional electron systems and its role in the photoresponse to microwave radiation

An analysis of the classical problem demonstrates that the current-pinch effect exists near one of the sides of a rectangular sample when the two-dimensional electron density has a gradient along the current direction and the ratio of the Hall component of the magnetoconductivity tensor to its dissipative component is large. This conclusion is confirmed by the numerical calculations. It has been shown that the results explain a number of experimental observations in the regime of microwave-induced states with near-zero dissipative components of the magnetoconductivity and magnetoresistivity tensors.