Session A1 - Microwave-Induced Resistance Oscillation in 2-D Electron Systems.
INVITED session, Monday morning, March 22
517A, Palais des Congres
Under a strong ac drive the zero-frequency linear response dissipative resistivity \rho_d(j=0) of a homogeneous state is allowed to become negative. We show that such a state is absolutely unstable. The only time-independent state of a system with \rho_d(j=0)<0 is characterized by a current which almost everywhere has a magnitude j_0 fixed by the condition that the nonlinear dissipative resistivity \rho_d(j_0)=0. As a result, the dissipative component of the dc-electric field vanishes. The total current may be varied by rearranging the current pattern appropriately with the dissipative component of the dc-electric field remaining zero. This result, together with the calculation of Durst et al., indicating the existence of regimes of applied ac microwave field and dc magnetic field where \rho_d(j=0)<0, explains the zero-resistance state observed by Mani et al. and Zudov et al..