Atomic scale crystal field mapping of polar vortices in oxide superlattices

Polar vortices in oxide superlattices exhibit complex polarization topologies. Using a combination of electron energy loss near-edge structure analysis, crystal field multiplet theory, and first-principles calculations, we probe the electronic structure within such polar vortices in [(PbTiO3)(16)/(SrTiO3)(16)] superlattices at the atomic scale. The peaks in Ti L-edge spectra shift systematically depending on the position of the Ti4+ cations within the vortices i.e., the direction and magnitude of the local dipole. First-principles computation of the local projected density of states on the Ti 3d orbitals, together with the simulated crystal field multiplet spectra derived from first principles are in good agreement with the experiments.

Automated summary

This research utilizes a combination of techniques to probe the electronic structure within polar vortices in oxide superlattices at the atomic scale, finding that the peaks in Ti L-edge spectra systematically shift depending on the position of the Ti4+ cations. First-principles computations and simulations derived from first principles show good agreement with experimental results.