On the happiness of ferroelectric surfaces and its role in water dissociation: the example of bismuth ferrite

TL;DR

This study uses density functional theory to explore how ferroelectric polarization affects the surface chemistry of bismuth ferrite, revealing potential for water splitting applications through polarization control.

Contribution

It provides a detailed analysis of surface stability and charge compensation mechanisms in bismuth ferrite, linking ferroelectric polarization to surface reactivity and water dissociation.

Findings

Stable surface geometries depend on termination and polarization direction.

Charged surfaces are stabilized by defects and adsorbates like water.

Potential for water splitting cycles via polarization switching.

Abstract

We investigate, using density functional theory, how the interaction between the ferroelectric polarization and the chemical structure of the (001) surfaces of bismuth ferrite influences the surface properties and reactivity of this material. A precise understanding ofthe surface behavior of ferroelectrics is necessary for their use in surface science applications such as catalysis as well as for their incorporation in microelectronic devices. Using the (001) surface of bismuth ferrite as a model system we show that the most energetically favoured surface geometries are combinations of surface termination and polarization direction that lead to uncharged, stable surfaces. On the unfavorable charged surfaces, we explore the compensation mechanisms of surface charges provided by the introduction of point defects and adsorbates, such as water. Finally, we propose that the special surface properties of bismuth ferrite (001) could be used to produce an effective water splitting cycle through cyclic polarization switching.