Minping Zhang

The electronic structure of LaCo2B2

The electronic structure of the recently discovered LaCo2B2 was studied from first-principles calculations. Our results indicate that the hybridization between Co-3d and B-2p is much stronger than that between Fe-3d and As-4p in LaOFeAs and BaFe2As2, which removes the magnetic ordering of Co ions. Therefore, the ground state of LaCo2B2 is nonmagnetic. At the Fermi level, the density of state of La-5d is very high and here are four bands cutting across the Fermi level, which are mostly derived from dz2−3r2 and dyz/zx orbitals. Such results are different with both LaOFeAs and BaFe2As2. The substitution of La by Y atoms would not change the ground state, while substitution of La with Sc atoms might induce a magnetic moment on the Co atom. Comparing with LuNi2B2C2, we classify LaCo2B2 as a BCS superconductor.