Semiconducting nonperovskite ferroelectric oxynitride designed <i>ab initio</i>

Recent discovery of HfO2-based and nitride-based ferroelectrics that are compatible to the semiconductor manufacturing process have revitalized field ferroelectric-based nanoelectronics. Guided by a simple design principle charge compensation density functional theory calculations, we discover HfO2-like mixed-anion materials, TaON NbON, can crystallize in polar Pca21 phase with strong thermodynamic driving force adopt anion ordering spontaneously. Both oxynitrides possess large remnant polarization, low switching barriers, unconventional negative piezoelectric effect, making them promising piezoelectrics ferroelectrics. Distinct from HfO2 has wide band gap, both NbON absorb visible light high carrier mobilities, suitable for ferroelectric photovoltaic photocatalytic applications. This new class multifunctional nonperovskite oxynitride containing economical environmentally benign elements offer platform optimize high-performing semiconductors integrated systems.