Speaker
Description
Ferroelectric Hafnium Oxide (HfO2) is a leading candidate for scalable nonvolatile devices, yet the microscopic origin of polarization switching in isovalently doped HfO2 remains incompletely understood. Here, we investigate Zr-doped HfO2 using first-principles density-functional theory by constructing ±P polarization endpoints and analyzing the real-space charge density ρ(+P), ρ(-P), and their difference ∆ρ=ρ(+P)-ρ(-P) in the xz-plane (averaged along y) for 3.125%, 6.25%, and 9.375% Zr concentrations. The charge density maps show oxygen-centered electron localization in both polarization states, confirming that the material remains insulating and predominantly ionic across all dopings. The ∆ρ distributions exhibit clear dipolar charge rearrangements around the anion sublattice, indicating that polarization reversal is governed by collective Hf/Zr–O displacement patterns rather than metallic charge transfer. Despite the persistence of a coherent switching-induced charge redistribution, the magnitude and spatial uniformity of ∆ρ evolve with Zr content, revealing a doping-dependent modulation of the local polar distortion network. In parallel, Berry-phase polarization analysis demonstrates that experimentally relevant switching polarization corresponds to a physically connected branch of the polarization lattice; a consistent branch correction (n=+1) is required to obtain meaningful switched polarization values for the calculated Zr-doped structures.
| Academic or Professional Status | Graduate Student |
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