Extrinsic nature of the polarization in hafnia ferroelectrics

Abstract

Hafnia and related fluorites defy our understanding of ferroelectricity, even if we restrict ourselves to the intrinsic properties of ideal crystals. Here we focus on a critical puzzle, namely, the sign of the electric polarization. Using first-principles simulations, we show that a polar hafnia layer with a fixed atomic configuration can give rise to depolarizing fields of either positive or negative sign, depending on the environment. This implies that (the sign of) the polarization in hafnia is extrinsic in nature. We explain this result and discuss its relevance to other ferroelectric families.

arXiv comment7 pages, 5 figures

References in corpus (8)

• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• VASPKIT: A User-friendly Interface Facilitating High-throughput Computing and Analysis Using VASP Code
• Ultrahigh oxygen ion mobility in ferroelectric hafnia
• Electrostatic stability of insulating surfaces: Theory and applications
• Theoretical approach to ferroelectricity in hafnia and related materials
• Cyclic Ferroelectric Switching and Quantized Charge Transport in CuInP${}_2$S${}_6$
• Triggered ferroelectricity in HfO${}_2$ from hybrid phonons and higher-order dynamical charges