The structural, electronic and magnetic properties of a symmetrical FeMoO terminated (001)-oriented slab of double perovskite Sr2FeMoO6

The structural, electronic and magnetic properties of a 9-layer symmetrical FeMoO terminated (001)-oriented slab of double perovskite Sr2FeMoO6 have been studied by using the first-principle projector augmented wave potential within the generalized gradient approximation taking into account the on-site Coulomb repulsive (U = 2.0 eV for Fe and 1.0 eV for Mo). An outward relaxation is observed for each layer of the first four layers and the accompanying layer's rumpling has a decreasing trend from layer 1 to layer 4. Along Fe–O–Mo–O–Fe or Mo–O–Fe–O–Mo chain, the oxygen atom is closer to the adjacent Mo atom than to the adjacent Fe atom. The half-metallic nature ensures the symmetrical FeMoO terminated (001)-oriented slab of double perovskite Sr2FeMoO6 to be a potential application in spintronic devices. The Jahn–Teller structural distortions and the outward relaxations lead to the differences between pz state and similar px and py states, between dxy state and similar dyz and dxz states as well as between dz2 and dx2 − y2. The reduction in the restrictions from the reduction in the number of the near neighbors, especially the vanishing of the nearest neighbor oxygen atom just above the transition-metal (TM) atoms on the first layer makes not only the remaining axial TM–O distances slightly shorter than the four equatorial TM–O distances but also shifts toward higher energy region the occupied up-spin and down-spin states with respect to the cases of the TM atoms on the third and fifth layers.

► An outward relaxation occurs for layer 1 to layer 4 with a decreasing rumpling.
► The O atom is closer to the adjacent Mo atom than to the adjacent Fe atom.
► Half-metallic nature ensures the Sr2FeMoO6 slab an application in spintronics.
► The bonding–antibonding splitting of t2g states is smaller than that of eg states.
► The Fe+ 3 and Mo+ 5 ions are in antiferromagnetic coupling.