Half metal to insulator transition driven by electron doping in Ba2FeReO6

The La doped Ba2FeReO6 has been investigated by using the first-principles. Our calculations indicated that with the increase of La doping, half metallic to insulating transition is observed from Ba2FeReO6, Ba1.5La0.5FeReO6 to BaLaFeReO6. The injection of electron mainly goes to Re t2g orbitals, while Fe 3d orbitals are nearly unchanged with the increase of La doping. The valence state of Fe is 3+ for doped and undoped cases. For Re, the valence state is 5+ in Ba2FeReO6, 4.5+ in Ba1.5La0.5FeReO6 and 4+ in BaLaFeReO6. The net magnetic moment decreases with the increase of La doping.