Enhanced spin-density wave in LaFeSbO from first principles

We predict atomic, electronic, and magnetic structures of a hypothetical compound LaFeSbO by first-principles density-functional calculations. It is shown that LaFeSbO prefers an orthorhombic stripe-type antiferromagnetic phase [i.e., spin-density wave (SDW) phase] to the tetragonal nonmagnetic (NM) phase, with a larger Fe spin moment and greater SDW-NM energy difference than those of LaFeAsO. In the NM-phase LaFeSbO, the electronic bandwidth near the Fermi energy is reduced compared with LaFeAsO, indicating smaller orbital overlap between Fed states and subsequently enhanced intra-atomic exchange coupling. The density of states at the Fermi energy is greatly increased and the calculated Fermi surface in the NM phase shows increased nesting between hole and electron sheets compared with LaFeAsO. Based on monotonous changes found in our calculated material properties of LaFePnO (Pn=P, As, and Sb) along with reported superconducting properties of doped LaFePO and LaFeAsO, doped LaFeSbO is possibly a candidate of superconductor with a higher superconducting transition temperature.