Key Words:SUPERCONDUCTIVITY
Abstract:Magnetic and electronic structures of K1-xFe2Se2 (x = 0.0, 0.2, 0.4, 0.6, and 0.8) in collinear antiferromagnetic state were studied by first-principles calculations. With the increase of K vacancy concentration, the magnetic moment and Fe-Se bond length were decreased (from x = 0.0 to 0.6) first and then increased (from x = 0.6 to 0.8). When the K vacancy concentration was 0.6 (that is K0.4Fe2Se2), the magnetic moment was completely suppressed, and the Fe-Se bond was the smallest. In contrast, the hybridized band width (HBW) first increased and then decreased, reaching to the maximum for K0.4Fe2Se2. The electron Fermi surface shrank gradually and the hole Fermi surface grew. The calculated results explained why experimental K0.8Fe2Se2 showed superconductivity compared with KFe2Se2.
Volume:35
Issue:9
Translation or Not:no