O_(2)在不同终端Fe_(31)MnC(001)表面吸附与解离的理论研究

Density Functional Theory of O_(2) Adsorption and Dissociation of Fe_(31)MnC(001) Surface

采用密度泛函理论中的广义梯度近似方法(GGA)研究了氧分子在Fe_(31)MnC(001)表面的3种不同吸附位(顶位、桥位和面心间位)的吸附行为和C对Fe_(31)Mn磁性的影响。通过吸附能结果发现,氧分子倾向于垂直吸附在四配位饱和的空穴位,而氧原子强烈吸附在相邻的四配位空穴中。以Mn为表层原子的表面均发生了氧分子的解离吸附,桥位吸附对应的吸附结构最稳定。C原子增加了基体的磁化强度杂化,抑制近邻Fe和Mn原子之间的反铁磁相互作用。

The absorptive characters of O_(2)on Fe_(31)MnC(001) surface at three different sits(top, bridge and hollow) and effect of C on the magnetic properties of Fe_(31)Mn were investigated by the generalized gradient approximation(GGA) based on density functional theory(DFT). The results indicate that O_(2)tends to be vertically over the four-coordination vacancy hollow site. For Oxygen atom adsorption, it has a larger adsorption energy when oxygen atoms occupy the adjacent four-coordination vacancy hollow site. The dissociative adsorption of oxygen molecules occurs on the surface with Mn as the surface atom, and the bridge adsorption is the most favorable adsorption site.Meanwhile, carbon atom not only increases the magnetization hybridization of matrix, but also inhibits antiferromagnetic interaction of the adjacent Fe and Mn atoms.