Atomically Resolved Mapping of Polarization and Electric Fields Across Ferroelectric/Oxide Interfaces by Z-contrast Imaging

摘要

Polarization dynamics at the ferroelectric-metal interfaces is the dominant factor underpinning the functionality of ferroelectric devices including capacitors,~([1,2]) direct probe-based data storage,~([3]) field-effect transistors,~([4-5]) and tunneling barriers.~([6-9]) In particular, multiple theoretical studies have addressed the role of mesoscopic space-charge layers,~([10]) non-uniform polarization distributions,~([11]) and chemical bonding.~([12]) Gerra et al.~([13]) have shown theoretically that the planar corrugations responsible for the dipole moment can propagate from the ferroelectric to the oxide component, effectively smearing the distribution of polarization bound charge. Tsymbal et al.~([14,15]) have demonstrated the role of interface bonding on dipole formation, painting a complex picture of multiple charge and polarization driven interactions even at nominally simple interfaces. Pruneda et al.~([16]) have also demonstrated that ferrodistortive cation off-centering can arise near the surfaces of metallic oxides.