DOI:
Authors:
Beatriz Moura Gomes, J Holtz, Marta L. Pinto, Maria Helena Braga
Abstract:
Abstract Understanding interfacial energetics and transport mechanisms in transition metal oxides is key to unlocking their potential in microelectronics, memory, and energy harvesting and storage. Here, a unified electrochemical potential scale is established for the group IVB oxides TiO 2 , ZrO 2 , and HfO 2 , combining spatially resolved scanning Kelvin probe microscopy with hybrid and density functional theory (DFT) simulations. These results show good agreement between DFT‐predicted absolute chemical potentials and experimental surface potentials across multiple electrode configurations and surface terminations. ZrO 2 exhibits unexpected emergent behavior under open‐circuit conditions, forming ordered potential patterns suggestive of internal charge separation and O δ ⁻ transport. TiO 2 shows dynamic sensitivity to contact polarity and termination, while HfO 2 reveals elevated, orientation‐dependent potentials linked to spontaneous ferroelectricity. Complementary temperature‐dependent conductivity and Hall effect measurements expose thermally activated polaronic transport (Fröhlich model), in all three oxides, including sharp transitions and topological conduction thresholds in HfO 2 . Simulated charge–discharge cycles further demonstrate field‐tunable conductivity and mobility. These findings redefine these oxides as active electrochemical materials, not merely inert dielectrics, and provide a predictive framework for rational interface design in reconfigurable electronics and ion–electron hybrid devices.