Electronic and magnetic structure of a possible iron based superconductor BaFe2Se3

We present results of LDA calculations (band structure, densities of states, Fermi surfaces) for possible iron based superconductor BaFe2Se3 (Ba123) in normal (paramagnetic) phase. Results are briefly compared with similar data on prototype BaFe2As2 and (K,Cs)Fe2Se2 superconductors. Without doping this system is anti-ferromagnetic with T (N) (exp) similar to 250 K and rather complicated magnetic structure. Neutron diffraction experiments indicated the possibility of two possible spin structures (antiferromagnetically ordered plaquettes or zigzags), indistinguishable by neutron scattering. Using LSDA calculated exchange parameters we estimate Neel temperatures for both spin structures within the molecular field approximation and show tau(1) (plaquettes) spin configuration to be more favorable than tau(2) (zigzags).