Transient currents in nematic liquid crystals

Transient currents induced by the polarity reversal of a dc voltage applied to a liquid-crystal cell have been experimentally studied. For voltages less than a characteristic value, the time occurrence of the peak current decreases with decreasing applied voltage, which is contrary to behavior expected for a normal carrier-transport process. To explain the experiments, a simple model based on the time variation of an applied voltage and the internal electric field induced by the adsorbed electric charges on the cell substrate has been proposed. The results from the model agree reasonably well with the experimental observations.