Accelerated Atomistic Kinetic Monte Carlo Simulations of Resistive Memory Arrays

Simulating emerging resistive switching memory devices, such as memristors, requires modeling frameworks that can treat the motion of point defects across nanoscale domains. Field-driven Kinetic Monte Carlo (d-KMC) methods that simulate the discrete structural evolution of atomic coordinates in the presence of external potential and heat fields can be used for this purpose. While physically similar to conventional KMC methods, field-driven approaches present different computational motifs and introduce global communication. Here, we develop the first scalable d-KMC code for resistive memory arrays at atomistic resolution. We accelerate this latency-sensitive simulation on the GPU partition of the LUMI Supercomputer, exploiting the high-speed interconnects between GPUs on the same node. Applied to the technologically relevant HfOx material stack, our code enables the first atomistic simulation of $3 \times 3$ arrays of resistive switching memory cells with more than 1 million atoms, matching the dimensions of fabricated structures.