Structural, magnetic, and electronic properties of EuSi₂ 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 EuSi₂ thin films on the Si(111) surface by ab initio calculations. Total energy calculations show that the EuSi₂ 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 6.96-7.00μ_B derived from the Eu-4f orbital electrons. Electronic band structure calculations indicate that the monolayer EuSi₂ thin film is a semiconductor with an indirect surface band gap of 0.45 eV, while the multilayer EuSi₂ 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.