Second-order nanoscale thermal effects in memristive structures based on poly-$p$-xylylene

Effects of second-order resistive switching in memristors based on poly-$p$-xylylene have been detected for the first time. It has been shown that these memristive structures constitute a dynamic system whose behavior significantly depends on second-order short-term effects. More precisely, the switching time of memristive structures decreases when a pair of pulses (not necessarily with the same polarities) are applied with a certain delay between the pulses. The second-order effects are explained by an increase in the local temperature of a metallic conducting bridge because of Joule heating. A three-dimensional numerical dynamic model involving the drift–diffusion of metal ions in the polymer matrix has been developed. The experimentally observed effects have been reproduced within this model. The results of this work demonstrate the possibility of using the revealed effects to develop neuromorphic computing systems.