Unlocking the Secrets of Nitride Perovskites

Nitride perovskites have been overshadowed by their oxide and halide cousins. This is a shame because they have a lot to offer. These materials are worth exploring for both scientific curiosity and practical applications. A recent study took a close look at lanthanum tungsten nitride (LaWN3). This was done using a method called density-functional theory. The focus was on the electronic and ferroelectric properties of thin films of this material. One surprising finding was an unusual quantum confinement effect in these thin films. This means that as the films get thinner, their electronic properties change in unexpected ways. This is not something seen in all materials. Another interesting discovery was that these thin films are strongly ferroelectric. This means they can have a spontaneous electric polarization that can be reversed by an external electric field. The strength of this ferroelectricity changes with the thickness of the film. The thinnest films showed a different way of maintaining their ferroelectric state compared to bulk materials. In these thin films, ferroelectricity is mainly caused by the interaction between tungsten and nitrogen atoms. So, what does this all mean? Well, by comparing nitride perovskites with oxide and halide perovskites, researchers can gain new insights. These insights can help understand the general rules that govern the properties of two-dimensional perovskites. This could lead to new technologies and a deeper understanding of these fascinating materials. It is a reminder that there is still much to learn and discover in the world of materials science.