  The electric conductivity behavior in the single and double tunnel-coupled
quantum wells (QW) with different doping profile caused by impact of short
pulses of the strong longitudinal (in the quantum wells plane) electric field
has been investigated. It is established that at low temperatures (4 K) after
such impact the long-term metastable state with increased electric conductance
may be observed in the case of the asymmetric QW couple with the impurity delta
shaped layer in the narrower QW. It is not observed in the structures with
other configurations. The observed effect is explained by the model accounting
for metastable changes in the electron energy states spectrum in the studied
structures caused by the strong electric field pulses.
