Hi guys, I am doing a RRAM simple modeling in Thermal-electric section now. The structure is metal-insulator-metal, and operated by applying voltage bias on top metal layer, resulting in formation or break of conductive filament(set and reset progress).

In one type of RRAM. The conductive filament formation is built by the random oxygen ions convening in insulation layer due to the strong voltage bias applied.

And I want to simulate this process, but the key question is that there is no free oxygen ions inside this layer(Frankly, these ions were generated by imperfect progress and imperfect insulators, I think~~~~~).

So, could anyone teach how to add these ions? or please feel free to correct some parts. Thanks!