Characteristics and transport mechanisms of triple switching regimes of TaOx memristor

While tantalum oxide (TaOx) memristors have shown superior multilevel switching performances and emerged as one of the leading candidates for analog memory and neuromorphic applications, its microscopic switching mechanisms at different resistance regimes remain obscure. In this work, electron transport mechanisms of TaOx memristors have been revealed by analyzing transport characteristics in three different resistance switching regimes. A quantum point contact model coupled with a first principles calculation has been validated to account for different conduction behaviors, which further sheds light on the evolution of the conducting filaments during switching processes. The high endurance observed in the low resistance switching regime is rationalized based on the observation of an enhanced instability and noise in the presence of a single conduction channel, i.e., quantum conductance G0=2e2/h.