Engineering Structural Discontinuity in Ordered Co3O4 Nanocube Arrays for Volatile Memristive Dynamics

The precise engineering of nanoscale gaps between discrete building blocks offers a deterministic pathway to govern charge transport physics in functional materials. Here, we demonstrate a fundamental transition from stochastic bulk conduction to reliable interface-mediated volatile switching by deliberately introducing structural discontinuity in spinel-type Co ₃ O ₄ nanocube (NC) arrays. While continuous oxide thin films suffer from irreversible breakdown and featureless transport, our self-assembled NC architecture enables a stable and low-power functional response. Utilizing an automated metrology framework based on the Segment Anything Model (SAM), we confirm the formation of a highly ordered, non-percolated square lattice with sub-nanometer precision in interparticle spacing. This structural determinism confines the active conduction volume to nanoscale junctions, achieving an ultralow operating current of 10 nA and exceptional statistical uniformity (coefficient of variation < 9%). Quantitative analysis identifies Schottky emission and Fowler-Nordheim tunneling at NC-gap-NC interfaces as the dominant mechanisms. Furthermore, time-resolved measurements reveal dual-mode relaxation dynamics characterized by microsecond electronic detrapping and long-term ionic back-diffusion, which facilitate complex temporal dynamics for biomimetic signal processing. Our findings suggest that nanogap-driven tunneling, rather than bulk percolation, can serve as a useful design principle for energy-efficient electronic primitives beyond conventional continuous media.