Direct Imaging of Charge Density Modulation in Switchable Two-Dimensional Electron Gas at the Oxide Hetero-Interfaces by Using Electron Bean Inline Holography.

摘要

SrTiO3 and LaAlO3 was made possible by advances in atomic layer controlled growth. These advances have led to the creation of atomically-abrupt interfaces between novel complex oxide materials. It has been demonstrated that the conducting layer can be localized within a few nm of the interface, and that the carrier concentration can be altered with an electric field and/or lattice strain. We have created a strong interdisciplinary collaboration with the expertise in US and Korea required to attack the fundamental issues in this exciting, emerging field. We have for the first time directly imaged the charge carrier densities and spatial distributions at the (001) LaAlO3/SrTiO3 heterointerfaces by in-situ TEM holography. The new understanding from this measurement will ultimately lead to the nm-scale writing of up and down polarization ferroelectric domains that permit the design of nonvolatile switchable devices. We envision logic devices and tunable metamaterials with switchable electron current based on 2D interface materials.