Abstract
Differential analysis of current–voltage characteristics, obtained on the surface of epitaxial
films of ferroelectric lead zirconate titanate (Pb(Zr0.2Ti0.8)O3) using scanning probe
microscopy, was combined with spatially resolved mapping of variations in local conductance
to differentiate between candidate mechanisms of local electronic transport and the origin of
disorder. Within the assumed approximations, electron transport was inferred to be determined
by two mechanisms depending on the magnitude of applied bias, with the low-bias range
dominated by the trap-assisted Fowler–Nordheim tunneling through the interface and the
high-bias range limited by the hopping conduction through the bulk. Phenomenological
analysis of the I –V curves has further revealed that the transition between the low- and
high-bias regimes is manifested both in the strength of variations within the I –V curves
sampled across the surface, as well as the spatial distribution of conductance. Spatial variations
were concluded to originate primarily from the heterogeneity of the interfacial electronic barrier
height with an additional small contribution from random changes in the tip–contact geometry
