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Title: Stabilizing polar phases in binary metal oxides by hole doping
The recent observation of ferroelectricity in the metastable phases of binary metal oxides, such as HfO2, ZrO2, Hf0.5Zr0.5O2, and Ga2O3, has garnered a lot of attention. These metastable ferroelectric phases are typically stabilized using epitaxial strain, alloying, or defect engineering. Here, we propose that hole doping plays a key role in the stabilization of polar phases in binary metal oxides. Using first-principles density-functional-theory calculations, we show that holes in these oxides mainly occupy one of the two oxygen sublattices. This hole localization, which is more pronounced in the polar phase than in the nonpolar phase, lowers the electrostatic energy of the system, and makes the polar phase more stable at sufficiently large concentrations. We demonstrate that this electrostatic mechanism is responsible for stabilization of the ferroelectric phase of HfO2 aliovalently doped with elements that introduce holes to the system, such as La and N. Finally, we show that spontaneous polarization in HfO2 is robust to hole doping, and a large polarization persists even under a high concentration of holes.  more » « less
Award ID(s):
2145797 1931610 1806147 2044049
PAR ID:
10472470
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
2023 American Physical Society
Date Published:
Journal Name:
Physical Review Materials
Volume:
7
Issue:
4
ISSN:
2475-9953
Page Range / eLocation ID:
044412
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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