Nanobatteries in redox-based resistive switches require extension of memristor theory

TLDR

Redox‑based nanoionic resistive memory cells (ReRAMs) are promising nano‑devices for memory, logic, and neuromorphic computing, and recent discoveries linking them to memristors have intensified research. The authors aim to demonstrate that nanoionic memristive elements are governed by non‑equilibrium states that create a nanobattery. They combine theoretical modeling and experimental measurements to show that nanoionic memristive elements are controlled by non‑equilibrium states forming a nanobattery. The study shows that memristor theory must be extended to explain non‑zero‑crossing I‑V curves, and that the nanobattery’s electromotive force critically affects nanoscale memory behavior, underscoring the need for its control in future devices.

Abstract

Redox-based nanoionic resistive memory cells (ReRAMs) are one of the most promising emerging nano-devices for future information technology with applications for memory, logic and neuromorphic computing. Recently, the serendipitous discovery of the link between ReRAMs and memristors and memristive devices has further intensified the research in this field. Here we show on both a theoretical and an experimental level that nanoionic-type memristive elements are inherently controlled by non-equilibrium states resulting in a nanobattery. As a result the memristor theory must be extended to fit the observed non zerocrossing I-V characteristics. The initial electromotive force of the nanobattery depends on the chemistry and the transport properties of the materials system but can also be introduced during ReRAM cell operations. The emf has a strong impact on the dynamic behaviour of nanoscale memories, and thus, its control is one of the key factors for future device development and accurate modelling.