Zero differential resistance state in 2D dimensional electron system in strong magnetic field.

We report the observation of a zero differential resistance state (ZDRS) in response to direct current above a threshold value $I>I_{th}$ applied to a two-dimensional system of electrons at low temperatures in a strong magnetic field. Entry into the ZDRS, which is not observable above several Kelvins, is accompanied by a sharp dip in the differential resistance. Additional analysis reveals instability of the electrons for $I>I_{th}$ and an inhomogeneous, non-stationary pattern of the electric current. We suggest that the dominant mechanism leading to the new electron state is a redistribution of electrons in energy space induced by the direct current.