Atomic-level Structural and Chemical Analysis of Abrupt Boundaries Based on Transmission Electron Microscopy

Abstract

Abrupt boundaries like atomically defined interfaces and surfaces have attracted tremendous attention due to their notable role as a fertile source of emergent phenomena that are not present in their bulk forms. To correlate the intriguing properties of abrupt boundaries with their structure and chemistry, researchers have used multimodal microscopy combined with spectroscopy as an indispensable tool because it allows atomic site-specific structural and chemical information to be obtained at the fundamental level. Sub-angstrom microscopy, which become an established technique for materials science during the last two decades enables us to explore what really happens in the heteroboundaries between materials with ultimate precision. The available data have leapt to multidimensional structures, such as three or four-dimensional data, over a conventional two-dimensional scheme, thus enabling direct visualization of the changes in the local crystal symmetry and the chemical potential. In this, I will introduce how powerfully the recent state-of-the-art microscopy techniques often combined with simulations can be used to elucidate the structural and the chemical behaviors of nanomaterials embracing abrupt boundaries, which have often been vaguely understood based on macroscopic measurements or theoretical interpretations without direct observation.