Ferroelectricity in Simple Binary Crystals

Abstract

The origin of ferroelectricity in doped binary crystals, Pb1−xGexTe, Cd1−xZnxTe, Zn1−xLixO, and Hf1−xZrxO2 is discussed, while no binary ferroelectrics have been reported except for two crystals, HCl and HBr. The ferroelectricity is induced only in doped crystals, which shows an importance of electronic modification in chemical bonds by dopants. The phenomenological and microscopic treatments are given for the appearance of ferroelectric activity. The discovery of ferroelectricity in binary crystals such as ZnO and HfO2 is of high interest in fundamental science and also in application for complementary metal–oxide semiconductor (CMOS) technology.

Keywords

• ferroelectric
• binary crystal
• ZnO
• HfO2
• mixed bond