Establishing an unobstructed conduit for hydrogen diffusion via the artificial design of material microstructure associated with boundary configuration and crystal orientation offers a powerful tuning knob for extensively accelerating the proton mobility and enhancing electronic phase modulations, thereby advancing the high-speed protonic device applications.
Abstract
Hydrogen-associated filling-controlled Mottronics within electron-correlated system provides a groundbreaking paradigm to explore exotic physical functionality and phenomena. Dynamically controlling hydrogen-related phase transitions through external fields offers a promising route for designing protonic devices in multidisciplinary fields but faces high-speed bottlenecks owing to slow bulk diffusion of hydrogens. Here, a promising pathway is presented to kinetically expedite the electronic state evolution in VO2 system by taking advantage of artificial microstructure design. Typically, inclined domain boundary configuration and c
R-faceted preferential orientation, simultaneously realized in VO2/Al2O3 (11¯$bar 1$02) heterostructure, significantly lower the diffusion barrier through creating an unobstructed conduit for hydrogen diffusion. As a result, the achievable switching speed through hydrogenation outperforms that of counterpart grown on widely-utilized c-plane Al2O3 substrate by 2–3 times, with resistive switching concurrently improved by an order of magnitude. Of particular interest, an anomalous uphill hydrogen diffusion observed for VO2 with a diffusion highway fundamentally deviates from basic Fick’s law, unveiling a deterministic role of hydrogen spatial distribution in tailoring electronic state evolution. The present work not only provides a powerful tuning knob for manipulating ionic evolution, endowing with great potential in designing advanced protonic devices, but also deepens the understanding of hydrogen-associated insulator-metal transition in electron-correlated systems.
Advanced Science, EarlyView. Read More
