The VNL provides user-friendly interface, it is not difficult to build a interface ystem. From pointview of physics, when one builds an interface system, the most important thing that should be taken care of is the lattice match. First, you should consider the lattice math between Ru and HfO2 according to their lattice constants and the crystal structures. To make the lattice mismathc smaller, one had better choose the proper surfaces of them and the surface area. Basically, you can follow the steps demonstrated for the construction of Fe-MgO-Fe.