Ultrahigh oxygen ion mobility in ferroelectric hafnia

Abstract

Ferroelectrics and ionic conductors are important functional materials, each supporting a plethora of applications in information and energy technology. The underlying physics governing their functional properties is ionic motion, and yet studies of ferroelectrics and ionic conductors are often considered separate fields. Based on first-principles calculations and deep-learning-assisted large-scale molecular dynamics (MD) simulations, we report ferroelectric-switching-promoted oxygen ion transport in HfO${}_2$, a wide-band-gap insulator with both ferroelectricity and ionic conductivity. Applying a unidirectional bias can activate multiple switching pathways in ferroelectric HfO${}_2$, leading to polar-antipolar phase cycling that appears to contradict classical electrodynamics. This apparent conflict is resolved by the geometric-quantum-phase nature of electric polarization that carries no definite direction. Our MD simulations demonstrate bias-driven successive ferroelectric transitions facilitate ultrahigh oxygen ion mobility at moderate temperatures, highlighting the potential of combining ferroelectricity and ionic conductivity for the development of advanced materials and technologies.

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Cited by in corpus (6)

• Progress in Computational Understanding of Ferroelectric Mechanisms in HfO${}_2$
• Origin of Interstitial Doping Induced Coercive Field Reduction in Ferroelectric Hafnia
• Theoretical lower limit of coercive field in ferroelectric hafnia
• Exploring the energy landscape of aluminas through machine learning interatomic potential
• Anharmonic thermodynamics redefines metastability and parent phases in ferroelectric HfO2
• Extrinsic nature of the polarization in hafnia ferroelectrics