Half-metallicity and magnetism of zinc-blende Cr-chalcogenide (001) surfaces: Density functional study

In this study, we present the results of first-principles calculations for the half-metallicity and the magnetism of zinc-blende Cr-chalcogenide (001) surfaces by using highly precise all-election full-potential linearized augmented plane-wave method within the generalized gradient approximation. Two differently terminated surfaces, Cr-terminated and VI(S, Se, Te, Po)-terminated surfaces, have been considered. We observed from the calculated density of states that both the Cr-terminated and VI-terminated (001) surfaces in ZB Cr-chalcogenides maintain the half-metallicity. The magnetic moments (3.99, 4.02; 4.04 and 4.06 AB for ZB CrS, CrSe, CrTe and CrPo compounds, respectively) of surface Cr atoms were enhanced by about 10 % compared to the center layer Cr atoms by the surface effect, but those of subsurface Cr atoms were reduced. A negative spin polarization was induced at the VI atoms sites.