Engineering Grain Boundary Commensurability for Ferroelectric Stabilization in Hafnia-Based Films
Year: 2026
Type: preprint
Abstract: Grain boundaries fundamentally dictate the macroscopic properties of polycrystalline materials by breaking long-range symmetry. In ferroelectrics, these structural discontinuities are conventionally considered as detrimental features that induce depolarization fields and accumulate defects, thereby suppressing or pinning local polarization. Here, we demonstrate that the commensurability of grain boundaries inherently governs the polar-orthorhombic phase stability in polycrystalline Hf0.5Zr0.5O2 (HZO) thin films. Using depth-resolved multislice electron ptychography, we map the three-dimensional (3D) phase distribution across diverse boundaries with atomic resolution, revealing that highly commensurate grain boundaries effectively suppress the nonpolar-tetragonal phase by compensating for lattice mismatch while mitigating geometric frustration. Monte Carlo simulations uncover the atomistic and energetic origins of polar-phase stabilization, showing that commensurate grain boundaries favor the polar-orthorhombic phase more strongly than other grain boundaries. Guided by this principle, we epitaxially engineer HZO thin films to promote the preferential formation of commensurate grain boundaries, resulting in an approximately 60% enhancement in the remanent polarization of ferroelectric devices. These findings provide direct 3D experimental and theoretical evidence that establishes grain boundary commensurability as a critical degree of freedom for designing functional interfaces, guiding the construction of novel ceramics and polycrystalline ferroelectrics.
Source: arXiv (Cornell University)
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Energy, Rice University, National Energy Research Scientific Computing Center, Office of Science, High Performance Research Computing, Texas A and M University, Office of Naval Research, Division of Materials Research, Division of Civil, Mechanical and Manufacturing Innovation, Basic Energy Sciences, Lawrence Berkeley National Laboratory
Awards: G102163711, Collaborative Research: Probing quasiparticle excitations in TMDC Moiré superlattices for revealing and understanding novel two-dimensional correlated phases, G1079818582, G1143651532, G122673668, G1286236842, G1286251239, G1563972504, Collaborative Research: Machine Learning-assisted Ultrafast Physical Vapor Deposition of High Quality, Large-area Functional Thin Films, G1677143136, G1797209618, G1863003419, G2618837358, G2893224341, G30714459, FuSe: Ultra-Low-Energy Logic-in-Memory Computing using Multiferroic Spintronics, G3477485686, G3967535168, G415683661, G4158950854, G419881185, G426311843, G42916606, G4501827968, G498139845, CAREER: Understanding Strain and Strain Relaxation Mechanisms in Complex Two-Dimensional Materials, G5076365615, G513797252, G5261056217, G5634181180, G6186058811, G650090426, G6652958823, G6918803902, G7354628648, G7583137537, G993149817
OpenAlex ID: W7215066989