Uncovering enhanced ferroelectricity: Substituent-driven design of wurtzite ZnO materials

Ferroelectricity has been observed in wurtzite ZnO (w-ZnO), and ionic substitution has emerged as an effective strategy to enhance the ferroelectricity and spontaneous polarization. There are few theoretical studies on the ferroelectricity of substituted w-ZnO. In this work, we employ first-principles calculations to systematically investigate the effects of w-ZnO substituted with group IIA, IIB, and VIA elements on its local structure, ferroelectric behavior, and electronic properties. Our results show that among the substituents considered, element Be is particularly effective in improving the ferroelectricity of w-ZnO, based on spontaneous polarization, potential barriers, and formation energy analysis. In addition, we further explore the impact of varying Be concentrations and find that high Be concentration leads to greater spontaneous polarization, higher potential barriers, and improved structural stability in Be-substituted w-ZnO. These findings provide a theoretical foundation for designing and optimizing substituted w-ZnO materials for advanced ferroelectric applications.