Half-Metallicity in CuCr2S4 Film: A Density Functional Study

Copper chromium chalcospinel (CuCr2S4) is a metallic ferromagnet with high Curie temperature and large magnetization. Due to these characteristics and highly spin-polarized electronic structure near the Fermi level, it has been considered as an attractive candidate for spintronic application. By using the first-principle calculations based on density functional theory, we discovered that a complete spin polarization, or the so-called half-metallicity, can be realized in (100) CuCr2S4 film. The results of electronic structure show that by decreasing the film thickness, the delocalized hybridization between Cu-d and S-p states is weakened, which shifts the valence band maximum of the minority spin to lower energy, and thus leads to the half-metallicity. Furthermore, the half-metallicity of the CuCr2S4 film is found to be robust with respect to different terminations and surface vacancies.