Switching mechanism in resistive random access memory by first-principles calculation using practical model based on experimental results

For the practical use of resistive random access memory (ReRAM), many formation/rupture models of conductive paths are proposed. In this paper, we report both the probability of conductive path formation on grain surfaces and the marked drastic change in conductivity caused by a small number of atoms migrating on grain surfaces, determined by using experimental and calculation results complementarily. Experimental results of resistive switching operating modes suggest that resistance changes at grain boundaries, to which our calculation results can give an explanation. The energy for the conductive change from a low-resistance state to a high-resistance state is estimated to be about 0.05 eV per surface atom, which is much smaller than the formation and migration energies of vacancies (1.44–4.42 eV) and is comparable to the estimated temperature of the conductive path in the reset process.