  Next generation telecommunication technologies would benefit from strong
piezoelectric and ferroelectric response in materials that are compatible with
nitride radio-frequency electronic devices. Ferroelectric oxides with
perovskite structure have been used in sensors and actuators for half a
century, and halide perovskites transformed photovoltaics research in the past
decade, but neither of them is compatible with nitride semiconductors. Nitride
perovskites, despite numerous computational predictions, have not been
experimentally demonstrated and their properties remain unknown. Here we report
the experimental realization of the first nitride perovskite: lanthanum
tungsten nitride (LaWN3). Oxygen-free LaWN3 thin films in a polar perovskite
structure are confirmed by spectroscopy, scattering, and microscopy techniques.
Scanning probe measurements confirm a large piezoelectric response and strongly
suggest ferroelectric behavior, making it the first stable nitride
ferroelectric compound. These results should lead to integration of LaWN3 with
nitride semiconductors for wireless telecommunication applications, while
enabling synthesis of many other predicted nitride perovskites.
