DFT+U Study of Stability and Electronic Properties of Antiferromagnetic States of Sr4V2O6Fe2As2.

We examine the magnetic stability and electronic properties of Sr4V2O6Fe2As2 in the antiferromagnetic order of V, including the A-type (A-AF) and the checkerboard-type (c-AF), within the LDA+U approximation. Contrary to other reports, our data disclose that A-AF is more stable than c-AF for J in the range of 1 1:2 eV and U between 7 and 8 eV; likewise c-AF is more stable for the (U; J) sets of J up to 0.2 eV and U in the range of 6 8 eV. There are numerous energy bands crossing the Fermi level in the c-AF phase, suggesting a strong inter-band scattering which affects the high Tc superconductivity. Particularly, the calculated band structures expose the formation of a Dirac cone. Besides, the Fermi surface in both phases shows the multi-sheets character consisting of several hole-like cylinders around -Z and electron-like sheets at M and X points. The electron localization function study reveals that electrons are distributed in the high anisotropic frame and a large itinerant character of Fe 3d and V 3d dominantly favors the superconductivity in Sr4V2O6Fe2As2. [ABSTRACT FROM AUTHOR]