Electronic structure and bonding in epitaxially stabilized cubic iron silicides.

摘要: We present an ab initio full-potential linearized augmented-plane-wave (FLAPW) study of the structural and electronic properties two bulk unstable compounds FeSi (CsCl structure) ${\mathrm{FeSi}}_{2}$ (${\mathrm{CaF}}_{2}$ which have recently been grown by molecular-beam epitaxy on Si(111). obtain equilibrium lattice constants 2.72 5.32 A\r{} for ${\mathrm{FeSi}}_{2}$, respectively. The density states (DOS) agrees well with experiment shows metallic behavior. In agreement a previous calculation, DOS large d at Fermi level, explaining instability phase. electron charge distributions reveal small transfer from Si to Fe atomic spheres in both compounds. While Fe-Si bond is indeed partially ionic, we show that distribution corresponds covalent accumulation region. reversed order bands respect understood terms crystal-field splitting Fe-Fe nearest-neighbor dd interactions CsCl structure, strong p--Fe bonding fluorite