Photoinduced switching of electrical conductivity and its memory effect in the organic conductor α-(BEDT-TTF)2I3: Dependence on voltage height and temporal width of pulsed voltages

Abstract: Unprecedented memory effect of photoinduced switching of the electrical conductivity in α-(BEDT-TTF)2I3 controlled by the temporal width of square-wave pulsed voltages was reported, where BEDT-TTF represents bis(ethylenedithio)tetrathiafulvalene [Iimori et al., 2009]. Here, further study has been done in order to examine whether the memory effect can be controlled by changing the height of the pulsed voltage. Threshold values in the voltage height for the occurrence of the memory effect are characterized as a function of the width of pulsed voltages. The relation between the threshold height and the pulse width can be altered by a load resistance connected to the sample in series in a measurement circuit. It is also argued that time profiles of current observed in response to the application of pulsed voltages are inconsistent with a scenario in which the memory effect is ascribed to a temperature rise of the sample caused by photoirradiation and the successive application of pulsed voltages, i.e., the memory effect is not a thermal effect. [Copyright &y& Elsevier]