Theoretical and experimental study of NbO2 nanoslice formation

We have used reactive magnetron sputtering to form NbO2 nanoslices. These unique nanostructures with the dominating diffractions peaks related to low surface energy NbO2 planes are self-assembled into two different populations: aligned and random nanoslices. To provide an explanation for the formation of these NbO2 nanoslices with respect to competitive growth of nanorods, we employed density functional theory based molecular dynamics. (1 1 0) and (0 0 1) surfaces together with the related nanoslices and nanorods were considered, corresponding to low and high surface energy configurations, respectively. For the (1 1 0) configuration, nanoslices are more stable at all temperatures (0 K-900 K), which is consistent with experimental observations. On the other hand, for the (0 0 1) configuration nanorods are more stable at and above room temperature. We suggest that the texture modulation is the physical origin of NbO2 nanostructure formation.