Structural Properties of Thin Nickel Iodide Film Synthesized on the Polycrystalline Nickel Surface Under Molecular Iodine Action in Ultrahigh Vacuum

In this work, we examined the structural properties of a thin nickel iodide film synthesized on polycrystalline nickel. The nickel foil substrate was chosen to simplify the technology for the production of two-dimensional ferromagnets as promising materials for the creation of low-power spintronic devices, which are widely demanded in systems of high-speed transmission and processing of big data. The studies were carried out in an ultrahigh-vacuum setup at Prokhorov General Physics Institute of the Russian Academy of Sciences (GPI RAS) using Auger electron spectroscopy, low-energy electron diffraction, scanning tunneling microscopy. The parameters of ion etching and annealing for cleaning the surface have been established. The effective method for the nickel surface restructuring leading to the formation of terraces with monatomic steps was proposed. The conditions for the growth of trilayer NiI2 are established. A method has been developed for creating samples containing a NiI2 trilayer on different nickel faces, which makes it possible to carry out studies using scanning tunneling spectroscopy for different nickel faces in the course of one experiment. The work may be of interest for optimizing the production of two-dimensional nanomaterials.