Nonequilibrium processes in semiconductors are considered with highly
nonuniform initial densities of charge carriers. It is shown that there exist
such distributions of charge densities under which the electric current through
a sample displays quite abnormal behaviour flowing against the applied voltage.
The appearance of this negative electric current is a transient phenomenon
occurring at the initial stage of the process. After this anomalous negative
fluctuation, the electric current becomes normal, i.e. positive as soon as the
charge density becomes more uniform. Several possibilities for the practical
usage of this effect are suggested.Comment: 1 file, 11 pages, RevTex, no figure