Polarizing oxygen vacancies in insulating metal oxides under high electric field

Abstract

We demonstrate a thermodynamic formulation to quantify defect formation energetics in an insulator under high electric field. As a model system, we analyzed neutral oxygen vacancies (color centers) in alkaline-earth-metal binary oxides using density functional theory, Berry phase calculations, and maximally localized Wannier functions. Work of polarization lowers the field dependent electric Gibbs energy of formation of this defect. This is attributed mainly to the ease of polarizing the two electrons trapped in the vacant site, and secondarily to the defect induced reduction in bond stiffness and softening of phonon modes. The formulation and analysis have implications for understanding the behavior of insulating oxides in electronic, magnetic, catalytic, and electrocaloric devices under high electric field.

This paper was accepted for publication in Physical Review Letters. A Link to the accepted abstract: https://journals.aps.org/prl/accepted/d7070Yf1Mfe1975061178757351719ba020145107

References in corpus (7)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• The Origin of Ferroelectricity in Hf${}_x$ Zr${}_{1-x}$ O${}_2$: A Computational Investigation and a Surface Energy Model
• Magneto-ionic Control of Interfacial Magnetism
• Static dielectric properties of carbon nanotubes from first principles
• Universal Fabrication of Two-Dimensional Electron Systems in Functional Oxides