Transition between large and small electron polaron at neutral ferroelectric domain walls in BiFeO${}_3$

Abstract

Ferroelectric domain walls are planes within an insulating material that can accumulate and conduct charge carriers, hence the interaction of the domain walls with the charge carriers can be important for photovoltaic and other electronic applications. By means of first principles calculations we predict a transition from a large two-dimensional electron polaron to a small polaron at the domain walls at a critical electron density, with polaron signatures in optical absorption and photoluminescence. We find that large and small polarons at the domain walls create different absorption peaks within the band gap that are not present in the case of pristine domain walls. These are an extended Drude peak in the case of large electron or hole polarons and a narrow mid-gap peak in the case of the small electron polaron.

arXiv commentThe main finding of the article, the transition between a large and a small electron polaron as a function of the polaron density, is an artefact, which resulted from applying an unsuitable methodology for modeling diluted polarons. This affects results depicted in Figs. 3, 4, 5, and 6

References in corpus (5)

• Linear and Nonlinear Optical constants of BiFeO_3
• Inter- and intra-layer excitons in MoS${}_2$/WS${}_2$ and MoSe${}_2$/WSe${}_2$ heterobilayers
• Domain walls in a perovskite oxide with two primary structural order parameters: first-principles study of BiFeO${}_3$
• Electron trapping by neutral pristine ferroelectric domain walls in BiFeO${}_3$
• Erratum: Photovoltage from ferroelectric domain walls in BiFeO${}_3$