Theoretical investigation on the surface and morphological properties of lead nickelate multiferroics: vacancy dependency

In the context of the development of materials, morphology control represents an important tool for tuning their properties, thus enabling their application on photocatalysis, energy conversion and other areas. In this work, DFT/B3LYP methodology was carried out to investigate the surface structure and the electronic, ferroelectric and magnetic properties of low index surfaces of the multiferroic PbNiO3 material at the R3c crystalline phase. The results indicate that the surface energy increases in the following the order (110) < (012) < (111) < (001) < (101) < (100). These results allow us to predict the available morphologies, finding that six theoretical morphologies correspond to those reported experimentally, while nine morphologies have not yet been reported experimentally. The properties of the exposed surfaces for each morphology can be associated with the number of oxygen vacancies (V-0), and the presence of uncoordinated [NiO6] and [PbO6] clusters.