The Energy Band Structure of A_xFe_2Se_2 (A = K, Rb) Superconductors

摘要

We study the band structure of antiferromagnetic A_xFe_2Se_2 (A = K, Rb) superconductors by using firstprinciples electronic structure calculations which is density functional theory. In the vicinity of iron-vacancy, we identify the valence electrons of A_xFe_2Se_2 will be filled up to the Fermi level and no semiconducting gap is observed. Hence, the A_xFe_2Se_2 is a metallic instead of semiconducting which leads to superconductivity in the orbital-selective Mott phase. Similarly, there is non-vanishing density of states at the Fermi level.