Spatiotemporal drift-diffusion simulations of analog ionic memristors

Abstract

Analog memristors that exhibit an electronic conductivity change in response to ionic motion have been simulated using the finite element method. Several physical mechanisms are considered for the redistribution of dopants within the device and all result in minimal resistance changes. The mechanisms considered that result in minimal resistance changes are initial ion concentration, hole mobility dependence on acceptor concentration, and geometry. In contrast, ion extraction results in a significant change in the simulated analog memristor resistance (many orders of magnitude). It is determined that if ions can be repeatedly cycled without damage to the crystal structure, ion extraction is the optimal analog ionic memristor operation mechanism. Given this conclusion, battery technology materials known for their robustness in spite of repeated ion extraction/replacement should be considered for reliable analog memristor applications.