115學年材料系-第十五週 專題研討課程 演講公告 (115年6月11日)
2026.06.09
115學年材料系-第十五週 專題研討課程 演講公告 (115年6月11日)
講者：郭錦龍 博士
現職：國立台灣大學材料科學與工程學系 教授
時間：6/11 (四) 15:20~17:10
地點: 成功大學 成功校區 三系館 鋼構區 (3F) 共同教室 A1302 演講廳
內容摘要:
This study employs first-principles calculations based on density functional theory to investigate the ferroelectric and antiferroelectric phase formation mechanisms in zirconia (ZrO₂). The thermodynamic stability of the polar orthorhombic phase (Pca2₁) and the nonpolar tetragonal phase (P4₂/nmc) is compared, revealing that polar and nonpolar structural characteristics do not necessarily correspond to the orthorhombic or tetragonal unit cell geometry. Under substrate constraint, the nonpolar-to-polar transition is modeled as a constant-volume process, and phonon calculations establish the unit cell size ranges conferring room-temperature stability for both phases. The temperature-dependent stability further accounts for the electric-field-induced phase transitions associated with antiferroelectric behavior. Kinetic suppression of the more stable monoclinic (P2₁/c) and antipolar orthorhombic (Pbca) phases is also examined: while the polar phase is not the thermodynamic ground state, lattice constraint modulates the phase transformation barriers, enabling the ferroelectric phase to nucleate and persist. Finally, free surface effects are found insufficient to explain the observed thickness-dependent properties. Instead, lattice constraint provides a self-consistent thermodynamic and kinetic framework that accurately predicts the thickness-dependent evolution of ferroelectric and antiferroelectric properties in ZrO₂ thin films.
題目: First-Principles Study on the Origins of the Ferroelectricity and Antiferroelectricity in ZrO2
講者：郭錦龍 博士
現職：國立台灣大學材料科學與工程學系 教授
時間：6/11 (四) 15:20~17:10
地點: 成功大學 成功校區 三系館 鋼構區 (3F) 共同教室 A1302 演講廳
內容摘要:
This study employs first-principles calculations based on density functional theory to investigate the ferroelectric and antiferroelectric phase formation mechanisms in zirconia (ZrO₂). The thermodynamic stability of the polar orthorhombic phase (Pca2₁) and the nonpolar tetragonal phase (P4₂/nmc) is compared, revealing that polar and nonpolar structural characteristics do not necessarily correspond to the orthorhombic or tetragonal unit cell geometry. Under substrate constraint, the nonpolar-to-polar transition is modeled as a constant-volume process, and phonon calculations establish the unit cell size ranges conferring room-temperature stability for both phases. The temperature-dependent stability further accounts for the electric-field-induced phase transitions associated with antiferroelectric behavior. Kinetic suppression of the more stable monoclinic (P2₁/c) and antipolar orthorhombic (Pbca) phases is also examined: while the polar phase is not the thermodynamic ground state, lattice constraint modulates the phase transformation barriers, enabling the ferroelectric phase to nucleate and persist. Finally, free surface effects are found insufficient to explain the observed thickness-dependent properties. Instead, lattice constraint provides a self-consistent thermodynamic and kinetic framework that accurately predicts the thickness-dependent evolution of ferroelectric and antiferroelectric properties in ZrO₂ thin films.