钴磷族化合物BaT2P2和BaT2As2(T=Co,Rh, Ir) 的电子结构

基于密度泛函理论(DFT)在广义梯度(GGA)下计算了钴磷族化合物BaT₂P₂和BaT₂As₂(T=Co, Rh, Ir)的电子结构.研究发现在BaCo₂P₂和BaCo₂As₂中,由于范霍夫畸点位于费米面附近使得费米能级处的态密度非常高,从而导致由斯通纳机理引起的巡游铁磁不稳定性.在从Co到关键词：电子结构范霍夫畸点斯通纳不稳定性

Electronic structures cobalt group pnictides: BaT2P2 and BaT2As2 (T=Co, Rh, Ir)

We study the electronic structure of cobalt pnictides: BaT₂P₂ and BaT₂As₂ (T=Co, Rh, Ir) by the density functional theory within generalized gradient approximation, and find that the ferromagnetisms in BaCo₂As₂ and BaCo₂P₂ are due mostly to the high density of states (Van-Hove singularity) at Fermi level, which induce Stoner ferromagnetism. In these compounds, from Co-3d to Rh-4d, then to Ir-5d, the d-d bonding and the d-p bonding in the TX₄(X=P, As) layers are strengthened. As a result, the antibonding d-d states are pushed away from the Fermi level, and the ferromagnetisms are suppressed in Rh and Ir compounds. The evolutions and the detailed electronic structures of these compounds are studied and compared, and spin orbital coupling interaction is negligible.