Performance Of The Spin-Dependent Krieger-Li-Iafrate Approximation In Jellium Slabs

The possible spin-polarized states of metallic jellium slabs have been studied by means of a Krieger-Li-Iafrate (KLI) approximation for the exchange potential. The stability of the different magnetic states has been determined by using a fixed-spin-moment method. Notably, in the search for solutions with different magnetizations, the KLI approximation leads to the sudden filling of electronic states for either majority or minority spin channels, and also to hysteresis effects, as the system crosses these points of discontinuity. These effects are completely missed by the local spin-density approximation (LSDA), which exhibits instead a continuous behavior. Close to the density corresponding to the Bloch instability of the homogeneous 3D electron gas, different exotic magnetic configurations appear, some of them featuring a spontaneous breaking of inversion symmetry around the slab center. As compared to the LSDA, the spin-dependent KLI approximation offers a moderate increase of the stability of a slab antiferromagnetic state.