Ruddlesden-Popper结构杂化非常规铁电体的研究进展

张碧辉, 刘小强, 陈湘明

Recent Progress of Hybrid Improper Ferroelectrics with Ruddlesden-Popper Structure

ZHANG Bihui, LIU Xiaoqiang, CHEN Xiangming

图2 (a)常规铁电相变和(b)非常规铁电相变的能量变化[23]

Fig. 2 Energetics of a transition from paraelectric to ferroelectric phase for (a) proper and (b) improper ferroelectric system[23] F represents thermodynamic free energy of the system, η represents atomic polarity displacement, and T represents temperature. The black line represents the free energy of T>TC, and the minimum value of the free energy is at η=0, indicating that it is a paraelectric phase. The red line indicates the free energy of T<TC, and the minimum value of the free energy is at η≠0, indicating that it is a ferroelectric phase. The three lines between black and red indicate the transition state between the paraelectric phase and the ferroelectric phase. Colorful figure is available on website.