Oxygen vacancies stabilized 180° charged domain walls in ferroelectric hafnium oxide

Xu, Zhongshan; Zhu, Xiaona; Zhao, Guo-Dong; Zhang, David Wei; Yu, Shaofeng

doi:10.1063/5.0179879

Cited by 2 publications

(1 citation statement)

References 44 publications

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“…This paper expands on that work and is the first to analyze the H–H and T–T DWs of HZO considering an MFM structure (with the preprint published in arXiv 24 ). After the pre-print publication, another work has analyzed H–H/T–T DWs in bulk configurations of HfO 2 25 .…”

Section: Introductionmentioning

confidence: 99%

Formation and energetics of head-to-head and tail-to-tail domain walls in hafnium zirconium oxide

Paul,

Saha,

Gupta

2024

Sci Rep

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Abstract180$$^\circ$$ ∘ domains walls (DWs) of head-to-head/tail-to-tail (H–H/T–T) type in ferroelectric (FE) materials are of immense interest for a comprehensive understanding of the FE attributes as well as harnessing them for new applications. Our first principles calculation suggests that such DW formation in hafnium zirconium oxide (HZO) based FEs depends on the unique attributes of the HZO unit cell, such as polar-spacer segmentation. Cross pattern of the polar and spacer segments in two neighboring domains along the polarization direction (where polar segment of one domain aligns with the spacer segment of another) boosts the stability of such DWs. We further show that low density of oxygen vacancies at the metal-HZO interface and high work function of metal electrodes are conducive for T–T DW formation. On the other hand, high density of oxygen vacancy and low work function of metal electrode favor H–H DW formation. Polarization bound charges at the DW get screened when band bending from depolarization field accumulates holes (electrons) in T–T (H–H) DW. For a comprehensive understanding, we also investigate their FE nature and domain growth mechanism. Our analysis suggests that a minimum thickness criterion of domains has to be satisfied for the stability of H–H/T–T DW and switching of the domains through such DW formation.

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Section: Introductionmentioning

confidence: 99%

Formation and energetics of head-to-head and tail-to-tail domain walls in hafnium zirconium oxide

Paul,

Saha,

Gupta

2024

Sci Rep

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Progress in computational understanding of ferroelectric mechanisms in HfO2

Zhu,

Ma,

Deng

et al. 2024

npj Comput Mater

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Since the first report of ferroelectricity in nanoscale HfO2-based thin films in 2011, this silicon-compatible binary oxide has quickly garnered intense interest in academia and industry, and continues to do so. Despite its deceivingly simple chemical composition, the ferroelectric physics supported by HfO2 is remarkably complex, arguably rivaling that of perovskite ferroelectrics. Computational investigations, especially those utilizing first-principles density functional theory (DFT), have significantly advanced our understanding of the nature of ferroelectricity in these thin films. In this review, we provide an in-depth discussion of the computational efforts to understand ferroelectric hafnia, comparing various metastable polar phases and examining the critical factors necessary for their stabilization. The intricate nature of HfO2 is intimately related to the complex interplay among diverse structural polymorphs, dopants and their charge-compensating oxygen vacancies, and unconventional switching mechanisms of domains and domain walls, which can sometimes yield conflicting theoretical predictions and theoretical-experimental discrepancies. We also discuss opportunities enabled by machine-learning-assisted molecular dynamics and phase-field simulations to go beyond DFT modeling, probing the dynamical properties of ferroelectric HfO2 and tackling pressing issues such as high coercive fields.

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Oxygen vacancies stabilized 180° charged domain walls in ferroelectric hafnium oxide

Cited by 2 publications

References 44 publications

Formation and energetics of head-to-head and tail-to-tail domain walls in hafnium zirconium oxide

Formation and energetics of head-to-head and tail-to-tail domain walls in hafnium zirconium oxide

Progress in computational understanding of ferroelectric mechanisms in HfO2

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