Existence of a quadruple point in a binary ferroelectric phase diagram

• Date:2025-04-30
• Title of Paper:Existence of a quadruple point in a binary ferroelectric phase diagram
• Journal:Physical Review B
• Summary:In experimentally measured temperature-composition ferroelectric phase diagrams of BaTiO 3-based binary systems, a quadruple point where cubic (C), tetragonal (T), orthorhombic (O), and rhombohedral (R) phases converge has been frequently reported in previous work. More interestingly, the quadruple points are experimentally found to behave as a critical point with large enhancement in properties. However, it has remained a fundamental question as to whether a quadruple point in a binary ferroelectric system defies the thermodynamic phase rule and whether such a point necessarily goes critical. In this study, it is demonstrated by Landau theory that a CTOR quadruple point in a binary ferroelectric system can only exist in the form of a unique type of critical point at which two first-order transition lines and two second-order ones meet, and such critical quadruple points do not defy the thermodynamic phase …
• Co-author:Xiaoqin Ke; Sen Yang; Yu Wang; Dong Wang; Luo Zhao; Jinghui Gao; Yunzhi Wang; Xiaobing Re n
• Volume:103
• Page Number:085132
• Translation or Not:No
• Date of Publication:2021-02-22