Ferroelectric polarization-driven ionic modulation enabling enhanced self-rectification in NiOx/HfO2−x: Al memristors

Abstract

Self-rectifying memristors, which integrate diode-like behavior to suppress sneak currents in crossbar arrays, are promising for high-density neuromorphic systems. However, conventional designs often suffer from nonlinear weight updates and stochastic switching due to filamentary or Schottky-based mechanisms. Here, we present a NiOx/HfO2−x:Al bilayer memristor utilizing ferroelectric polarization to actively direct oxygen vacancy migration, thereby enhancing self-rectification. The polarization-induced internal field drives oxygen vacancy migration and synergizes with oxygen ion migration to modulate the interface barrier, yielding ∼3.5× larger rectification ratio than a non-ferroelectric control device. This ferroelectric–ionic coupling also achieves highly linear analog conductance updates (R2 ≈ 0.99, nonlinearity factor α ≈ 0.02). Our work reveals a ferroelectric–ionotronic mechanism that enables deterministic memristor switching, contributing to the evolving framework of neuromorphic device physics.