An optical method for simulating nonuniform systems

Model experiments of a new type in the physics of nonuniform systems are proposed. The method is based on the production of a randomly nonuniform distribution of charge carriers in a uniform semiconductor by means of photoexcitation with a nonuniform radiation flux. The method makes it possible to vary easily the character of the nonuniformities over wide limits. It has been used to investigate the effective transverse conductivity of nonuniform p-Si plates in a magnetic field (H). An anomalous transverse conductivity, previously predicted in a number of theoretical works, has been observed. As the electric field (E) increases, the anomalous conductivity decreases as a result of smoothing of the nonuniformities. The nonuniformities have virtually no effect on the conductivity in an open Hall circuit regime.