Electron-hole asymmetry and quantum critical point in hole-doped BaFe2As2

We show, from first-principles calculations, that the hole-doped side of Fe-As-based compounds is different from its electron-doped counterparts. The electron side is characterized as an itinerant metal with Fermi surface nesting, and SDW-to-NM quantum critical point (QCP) is realized by doping. For the hole-doped side, on the other hand, orbital-selective magnetic ordering develops together with checkboard anti-ferromagnetic (AF) ordering without lattice distortion. A unique SDW-to-AF QCP is achieved, and the J(2) = J(1)/2 criterion ( in the approximate J(1)&J(2) model) is satisfied at a hole-doping level of about x = 0.7. The observed superconductivity is located in the vicinity of QCP for both sides. Copyright (C) EPLA, 2008