Ion dynamics in metal halide perovskites for resistive-switching memory and neuromorphic memristors

Resistive-switching (RS) memory devices, or memristors, necessitate active materials of which electronic resistance is tunable by an external electric field. Metal halide perovskites (MHP) are representative RS materials wherein the electronic resistance is modulated by migration of intrinsic native or extrinsic impurity mobile ions. Since the first demonstration of MHP-based RS memory nearly a decade ago, MHPs have proven their great potential for energy-efficient nonvolatile memory devices. Dynamic transport of the mobile ions further allows MHPs to exhibit multistate resistance tunability at multiple timescale, which can be harnessed for neuromorphic memristors. Herein, we provide a comprehensive review on progress in RS memory devices with MHPs and their applications for neuromorphic memristors. We discuss how the electronic resistance of the MHPs is modulated by dynamic mobile ions, and focus on the ionic-electronic correlation that involves doping phenomena in MHPs on account of previous theoretical predictions and experimental verifications. Finally, we provide our perspective on major hurdles of MHPs for real-world applications of emerging nonvolatile memory and neuromorphic memristor technology.