Zero-differential conductance of two-dimensional electrons in crossed electric and magnetic fields

An electronic state with zero-differential conductance is found in nonlinear response to an electric field $E$ applied to two dimensional Corbino discs of highly mobile carriers placed in quantizing magnetic fields. The state occurs above a critical electric field $E>{E}_{th}$ at low temperatures and is accompanied by an abrupt dip in the differential conductance. The proposed model considers a $local$ instability of the electric field $E$ as the origin of the observed phenomenon. Comparison between the observed electronic state and the state with zero differential resistance, occurring in Hall bar geometry, indicates that the nonlinear response of edge states and/or skipping orbits is not essential in the studied samples. The result confirms that quantal heating is the dominant nonlinear mechanism leading to electronic states with both zero differential resistance and conductance.