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Electronic and magnetic structures in metallic thin films

2000; American Physical Society; Volume: 62; Issue: 1 Linguagem: Inglês

10.1103/physrevb.62.500

1095-3795

K. Okazaki, Y. Teraoka,

Physics of Superconductivity and Magnetism

Electronic and magnetic structures in metallic thin films are theoretically studied using the planar uniform jellium model on a basis of the spin density functional theory. The electron density, the spin density, and the effective potential are self-consistently calculated as functions of the film thickness D within a framework of the local spin density approximation. Several states, such as nonmagnetic (N), fully polarized ferromagnetic (FPF), partially polarized ferromagnetic (PPF), and antiferromagnetic (AF) states, are found as solutions of the Kohn-Sham equation. FPF and AF state have spin polarization over all the films, on the other hand, the spin polarization in PPF state is localized near the surfaces. It is found that an AF film with D consists of two FPF films with $D/2.$ By comparing the total energies, the ground state is determined as a function of D: FPF at $D<~9.0$ (in the atomic unit), N at $9.0<D<~11.9,$ PPF at $11.9<D<~12.8,$ FPF at $12.8<D<~16.4,$ PPF at $16.4<D<~17.1,$ N at $17.1<D<~22.1,$ PPF at $22.1<D<~25.6,$ and N at $25.6<D$ for ${r}_{s}=6,$ where ${r}_{s}$ is the Wigner sphere radius. The ground state of a very thin film is FPF, whatever value the average electron density over the film takes. Alkali metal thin films, especially, Cs and Rb thin films are expected to be ferromagnetic.