Switching dynamics in titanium dioxide memristive devices

TLDR

Memristive devices, such as TiO₂‑based bipolar resistive switches, are promising nanoelectronic components for nonvolatile memory, defect‑tolerant circuitry, and neuromorphic computing, characterized by a pinched hysteresis loop in their current‑voltage behavior. The study aims to use the mathematical definition of a memristive device to understand bipolar switching physics and derive formulas for predicting electrical and dynamical properties. The authors used electrical characterization and state‑evolution measurements to capture switching dynamics and relate them to drift‑diffusion models of ionized dopant vacancies in the oxide film. The analysis showed that the switching energy of a metal‑oxide memristor decreases exponentially as the applied current increases.

Abstract

Memristive devices are promising components for nanoelectronics with applications in nonvolatile memory and storage, defect-tolerant circuitry, and neuromorphic computing. Bipolar resistive switches based on metal oxides such as TiO2 have been identified as memristive devices primarily based on the “pinched hysteresis loop” that is observed in their current-voltage (i-v) characteristics. Here we show that the mathematical definition of a memristive device provides the framework for understanding the physical processes involved in bipolar switching and also yields formulas that can be used to compute and predict important electrical and dynamical properties of the device. We applied an electrical characterization and state-evolution procedure in order to capture the switching dynamics of a device and correlate the response with models for the drift diffusion of ionized dopants (vacancies) in the oxide film. The analysis revealed a notable property of nonlinear memristors: the energy required to switch a metal-oxide device decreases exponentially with increasing applied current.