四方晶系
铁电性
材料科学
相变
氧气
相(物质)
物理
凝聚态物理
电介质
光电子学
量子力学
标识
DOI:10.1103/physrevlett.130.096801
摘要
Defects such as oxygen vacancy are widely considered to be critical for the performance of ferroelectric ${\mathrm{HfO}}_{2}$-based devices, and yet atomistic mechanisms underlying various exotic effects such as wake-up and fluid imprint remain elusive. Here, guided by a lattice-mode-matching criterion, we systematically study the phase transitions between different polymorphs of hafnia under the influences of neutral and positively charged oxygen vacancies using a first-principles-based variable-cell nudged elastic band technique. We find that the positively charged oxygen vacancy can promote the transition of various nonpolar phases to the polar phase kinetically, enabled by a transient high-energy tetragonal phase and extreme charge-carrier-inert ferroelectricity of the polar $Pca{2}_{1}$ phase. The intricate coupling between structural polymorphism kinetics and the charge state of the oxygen vacancy has important implications for the origin of ferroelectricity in ${\mathrm{HfO}}_{2}$-based thin films as well as wake-up, fluid imprint, and inertial switching.
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