Spontaneous polarization enhancement in ferroelectric Hf0.5Zr0.5O2 using atomic oxygen defects engineering: An <i>ab initio</i> study

Abstract

Oxygen defect impacts on ferroelectricity in Hf0.5Zr0.5O2 (HZO) are systematically studied on the basis of first-principles calculations. Importantly, the oxygen vacancy and Frenkel pair could enhance the spontaneous polarization (Ps) by an average of 14.5%, while Oi could largely reduce Ps of HZO by 44.8% on the contrary. The altered Ps and, accordingly, the remanent polarization (Pr) agree well with the experimental results of polarization variability. Oxygen vacancy induced Pr enlargement is revealed to be the underlying mechanism responsible for the wake-up effect. Our results provide a guideline to boost the ferroelectricity via defect engineering in ferroelectric HZO.