Probing Materials Functionality with Aberration-Corrected STEM and First-Principles Theory

摘要: The successful correction of lens aberrations has greatly advanced the ability of the scanning transmission electron microscope (STEM) to provide direct, real space imaging at atomic resolution [1]. Data generated by aberration-corrected STEM is ideally suited for interpretation through density functional theory (DFT), a strategy that can provide the deepest insights into the origin of materials properties, especially in low-dimensional systems such as defects, interfaces, nanostructures and point defects. Interfaces in complex oxide heterostructures show many surprising properties. Aberration corrected STEM images can provide (projected) atomic coordinates with precision of a few pm. Examples will be shown of BiFeO3, mapping polarization, lattice parameter and octahedral rotations across interfaces unit cell by unit cell [2], and the origin of colossal ionic conductivity in SrTiO3/Y2O3-stabilized ZrO2 superlattices [3-5 …