Characterization of interfacial charge accumulation in ferroelectric BaTiO$_3$/manganite interfaces using atomic-resolution annular bright field imaging and electron energy-loss spectroscopy

Interfaces in functional oxides have been the focus of many studies due to potential emergence of novel phases. In this study, we will focus on ferroelectric/manganite, more specifically the LaSrMnO$_3$/BaTiO$_3$ interfaces in single-crystal thin films grown on SrTiO$_3$. Using atomic-resolution annular bright field (ABF) imaging, as well as atomic-column resolved electron energy-loss spectroscopy in the aberration-corrected, cold-field emission gun JEOL ARM200CF, we will demonstrate that the interfacial accumulation/depletion of charges, depending on the orientation of the ferroelectric polarization, can be directly quantified. We find that the interfacial accumulation of electron/holes is screen within three unit-cells of LaSrMnO$_3$. Moreover, using ABF imaging, we will shows that the distortions of the oxygen sublattice can be directly quantify, in both the BaTiO$_3$ layer, as well as the interfacial LaSrMnO$_3$. Our experimental results imaging and spectroscopy results will be complemented by first-principles density functional theory calculations.