Behavior of iron deposition on the surface structure and electrical properties of CrBr₃ by scanning tunneling microscopy and spectroscopy

Chromium Tribromide (CrBr₃) is a well-known material due to its magnetic properties. However, the low Curie temperature of CrBr₃ limited its development for electronic devices. Therefore, one possible solution to overcome this limitation is to introduce a heterostructure by incorporating metallic elements. In this study, we fabricate the CrBr₃/HOPG heterostructure by mechanical exfoliation and dry transfer techniques, and we conduct the deposition of iron atoms onto the surface of the heterostructure. Investigating the surface morphology and electrical properties using scanning tunneling microscopy and scanning tunneling spectroscopy. Our result revealed the morphology of CrBr₃ ranging from monolayer to multiple-layer thicknesses. Numerous irregular patterns with widths of 2–3 nm on the platform, and the atomic structure became highly resolved after iron deposition. The top-layer and bottom-layer bromine atoms surrounding the hexagonal arrangements formed by intermediate-layer chromium atoms are present. In terms of electrical properties, iron deposition caused significant changes to the energy band gap of CrBr₃, which decreased abruptly from 1.837±0.058 eV to 0.148±0.024 eV, indicating that a transition from a p-type semiconductor to semi-metal occurred. Our research supports the simulation of density functional theory in describing the electrical properties of CrBr₃ in previous research.