B23-O-02Atomic Level One-dimensional Structural Modulations at the Negatively Charged Domain Walls in BiFeO3 Films

Abstract

Domain walls (DWs) in ferroelectrics are known to exhibit various intriguing properties which are remarkably different from those in bulk [1, 2]. Depending on the orientations of DWs, the dipole configurations beside DWs can either be ‘head-to-tail’, ‘head-to-head’ or ‘tail-to-tail’ which then introduce zero, net positive or net negative bound charges at the DWs, respectively. Charged domain walls (CDWs) show great potentials to mediate the properties of ferroelectrics [3, 4]. Understanding the structures and properties of CDWs at an atomic scale is crucial for the exploration of novel applications. In this work, employing aberration-corrected scanning transmission electron microscopy, we found tail-to-tail CDWs at 71°, 109°, and 180° domains in BiFeO3 thin films. Two-dimensional mappings demonstrate one-dimensional structural modulations at these CDWs and reveal a stark contrast to uncharged domain walls. These findings are expected to broaden the range of both scientific and technical knowledge in nano ferroelectrics. [1] G. Catalan, et Figure: 1D structural