Electronic Properties of W’ Twin Walls in Ferroelastic BiVO₄

Abstract

Topological defects in ferroic materials can exhibit intrinsic properties that differ from the bulk. Here， structural and electronic variations of non‐prominent (W’) ferroelastic twin domain walls are investigated in BiVO4, a widely investigated photocatalytic material. Using aberration‐corrected scanning transmission electron microscopy (STEM), a kink configuration of the sharp ferroelastic twin wall with an altered electronic structure is revealed. Nanoscale conductivity measurements by conductive atomic force microscopy (c‐AFM) show higher conductivity at twin walls compared to non‐conductive bulk domains. Electronic structure investigation by electron energy loss spectroscopy (EELS) shows a higher density of oxygen vacancies and possible polaron accumulation at the wall. These findings reveal the electronic properties of BiVO4 domain walls, which are interesting for nanoscale‐engineered catalytic concepts of BiVO4 and materials design for photochemistry‐relevant applications.