Dielectric response of BaTiO3 electronic states under AC fields via microsecond time-resolved X-ray absorption spectroscopy

TL;DR

This study uses time-resolved X-ray absorption spectroscopy to investigate the dynamic electronic states of BaTiO3 under AC electric fields, revealing atom-specific contributions to polarization reversal.

Contribution

First experimental verification of Ba's electronic contribution to polarization reversal in BaTiO3 using time-resolved spectroscopy.

Findings

Eg peak and shoulder intensities increase with electric field amplitude

Main peak intensity decreases as eg peak increases

Spectral features reflect hybridization of Ti 3d with O 2p and Ti 4p

Abstract

For the first time, the dielectric response of a BaTiO3 thin film under an AC electric field is investigated using time-resolved X-ray absorption spectroscopy at the Ti K-edge to clarify correlated contributions of each constituent atom on the electronic states. Intensities of the pre-edge eg peak and shoulder structure just below the main edge increase with an increase in the amplitude of the applied electric field, whereas that of the main peak decreases in an opposite manner. Based on the multiple scattering theory, the increase and decrease of the eg and main peaks are simulated for different Ti off-center displacements. Our results indicate that these spectral features reflect the inter- and intra-atomic hybridization of Ti 3d with O 2p and Ti 4p, respectively. In contrast, the shoulder structure is not affected by changes in the Ti off-center displacement but is susceptible to the effect of the corner site Ba ions. This is the first experimental verification of the dynamic electronic contribution of Ba to polarization reversal.