  The non-Markov processes widely exist in thermodymanic processes, while it
usually requires packing of many transistors and memories with great system
complexity in traditional device architecture to minic such functions.
Two-dimensional (2D) material-based resistive random access memory (RRAM)
devices show potential for next-generation computing systems with much-reduced
complexity. Here, we achieve the non-Markov chain in an individual RRAM device
based on 2D mica with a vertical metal/mica/metal structure. We find that the
internal potassium ions (K+) in 2D mica gradually move along the direction of
the applied electric field, making the initially insulating mica conductive.
The accumulation of K+ is tuned by electrical field, and the 2D-mica RRAM
possesses both unipolar and bipolar memory windows, high on/off ratio, decent
stability and repeatability.Importantly, the non-Markov chain algorithm is
established for the first time in a single RRAM, in which the movement of K+ is
dependent on the stimulated voltage as well as their past states. This work not
only uncovers the inner ionic conductivity of 2D mica, but also opens the door
for such novel RRAM devices with numerous functions and applications.
