Potential of ZrO2 and HfO2 materials for nonlinear optical applications: First-principles study and experimental challenges

Abstract

The discovery of ferroelectricity in Hafnia (HfO2) and Zirconia (ZrO2) in 2011 raises the question of using these materials in photonic applications due to their compatibility with silicon. In this study, we used first-principles calculations to investigate and report on the electro-optic properties of the ferroelectric orthorhombic Pbc21 and rhombohedral R3m phases of ZrO2 and HfO2. We considered three main contributions to the Pockels effect: electronic, ionic, and piezoelectric. The highest Pockels coefficient of approximately 12 pm/V was found in pure ZrO2. We discuss the potential ways to increase the electro-optic response of ZrO2/HfO2-based materials and the experimental challenges of stabilizing the ferroelectric phase in these materials.