Structural, magnetic, and electronic properties of EuSi 2 thin films on the Si(111) surface.

Searching for magnetic silicide thin films has long been a hot topic in condensed matter physics and materials science based on their fundamental physics and promising device applications. Here we report a systematic study on the structural, magnetic, and electronic properties of EuSi 2 thin films on the Si(111) surface by ab initio calculations. Total energy calculations show that the EuSi 2 thin film in AA stacking is more favorable than that in AB or ABC stacking. The Eu 2 + ions are coupled ferromagnetically within each layer and antiferromagnetically across the adjacent silicene layers with a large local spin moment of 6.96-7.00 μ B derived from the Eu-4f orbital electrons. Electronic band structure calculations indicate that the monolayer EuSi 2 thin film is a semiconductor with an indirect surface band gap of 0.45 eV, while the multilayer EuSi 2 thin films exhibit metallic behavior. These findings provide a systematic understanding of rare-earth metal silicides on the Si surface and will provide guidance for Si-based nanoelectronics and spintronics.